one preferred embodiment of the present invention will now be described with reference to the drawings . fig1 is a bottom view showing one preferred embodiment of a connector of the invention . fig2 is a front view of the connector of fig1 fig3 is a side view of the connector of fig1 fig4 is a partly cross - sectional , plan view of a mating connector of fig1 and fig5 is a front view of the mating connector of fig1 . in fig1 reference numeral 21 denotes the connector of the present invention . the connector 21 can be electrically connected to the mating connector 22 adapted to be fixedly mounted on a wiring board ( not shown ). the connector 21 comprises a plurality of female connection terminals 23 , a housing body 24 for receiving these connection terminals 23 , and a spacer 25 attached to the housing body 24 so as to doubly retain the connection terminals 23 . the spacer 25 can be attached to the housing body 24 of the connector 21 from the lower side thereof at which a lower wall 26 is provided . the spacer 25 has a front holder 28 integrally connected thereto through hinges 27 ( see fig2 also ), and this front holder 28 can be fitted on a front portion of the housing body 24 . the front holder 28 serves as a stopper for the connection terminals 23 mounted in the housing body 24 . the connector 21 has a pair of finger pads 29 ( see also fig2 and 3 ) formed on the housing body 24 , and the connector 1 can be pushed into the mating connector , with the fingers held respectively on the finger pads 29 , so as to be connected to the mating connector 22 . when the connector 21 is connected to the mating connector 22 , connection terminals 31 ( described later ) in the mating connector 22 are inserted into the housing body 24 through the front holder 28 , and are electrically connected to the connection terminals 23 , respectively . the mating connector 22 comprises the plurality of male connection terminals 31 , soldered at their one ends to the wiring board ( not shown ), and a box - shaped connector housing 32 receiving the other end portions of the connection terminals 31 , that side of the connector housing 32 to be opposed to the connector 21 being open . as shown in fig4 the plurality of connection terminals 31 are fixed to a rear end wall 33 of the connector housing 32 , and project from this end wall 33 toward the open end of the connector housing 32 . these connection terminals are arranged in two ( upper and lower ) rows ( see fig5 ). each of the connection terminals 31 is bent into an l - shape . as shown in fig4 and 5 , the connector housing 32 is molded of a synthetic resin , and a lock portion 35 is formed on an upper wall 34 of this connector housing . deep - groove guides 36 , as well as shallow - groove guides 37 , are formed in the upper wall 34 , and are disposed on opposite sides of the lock portion 35 , respectively . fixing portions 39 ( see fig1 also ) for the wiring board ( not shown ), as well as a support portion 40 ( see fig1 also ), are formed integrally on a lower wall 38 opposed to the upper wall 34 . shallow - groove guides 41 and 41 are formed in the lower wall 38 , and are disposed on opposite sides of the support portion 40 , respectively . the guides 37 , 38 and 41 communicate with a fitting portion 42 for receiving the connector 21 ( see fig1 ). a screw hole 43 ( see fig1 ) is formed in each of the fixing portions 39 . the support portion 40 is adapted to be held in contact with the wiring board ( not shown ) so as to prevent the shaking of the mating connector 22 . referring back to fig1 the connector 21 is designed such that the widthwise dimension ( right - left direction ) is reduced , while maintaining a sufficient retaining force for retaining the spacer 25 . to achieve this , the pair of finger pads 29 are utilized . since the connector 21 is formed into a compact design , the mating connector 22 for fitting on the connector 21 is also formed into a compact design . in the present specification , the terms “ upper , lower , right , left , front and rear ” are defined as follows . the housing body 24 serves as a reference . in fig3 that side , to which the spacer 25 is attached , is “ the lower side ”. therefore , that side opposite to the lower wall 26 ( see fig1 ) is “ the upper side ”. when the connector of fig2 is normally seen , the left side is “ the left side ” while the right side is “ the right side ”. in fig1 that side of the connector to be opposed to the mating connector 22 is “ the front side ”, and that side of the connector , in which the connection terminals 23 are inserted , is “ the rear side ”. the above constituent members will be described below in detail . the connection terminals 23 , the housing body 24 and the spacer 25 will be described in this order . the connection terminal 23 is formed by pressing an electrically - conductive metal sheet into a predetermined shape , and the terminal 23 includes an electrical contact portion 45 and a wire connection portion 46 , as shown in fig1 and 3 . the electrical contact portion 45 is formed into a rectangular box - like shape , and has a resilient contact piece portion ( not shown ) provided therein . a rectangular hole 48 is formed in a lower wall 47 of this electrical contact portion 45 , and a lance 93 ( see fig9 ), which will be described later , can be engaged in the rectangular hole 48 . although not shown in the drawings , an opening , through which the connection terminal 31 in the mating connector 22 , can be inserted , is formed in a distal end of the electrical contact portion 45 . when the connection terminal 31 in the mating connector 22 is inserted into the electrical contact portion 45 through the distal end thereof , the connection terminal 31 is brought into contact with the resilient contact piece portion ( not shown ). the wire connection portion 46 is formed in continuous relation to the electrical contact portion 45 , and a shoulder portion 49 for retaining engagement with the spacer 25 is formed at an interconnecting portion interconnecting the electrical contact portion 45 and the wire connection portion 46 . that portion of a wire 50 , at which a conductor is exposed , is press - held by the wire connection portion 46 . next , the housing body 24 will be described with reference to fig6 to 11 . fig6 is a plan view of the housing body , fig7 is a bottom view of the housing body , fig8 is a front view of the housing body , fig9 is a cross - sectional view taken along the line a — a of fig8 fig1 is a rear view of the housing body , and fig1 is a cross - sectional view taken along the line b — b of fig8 . like the mating connector housing 32 ( see fig4 or 5 ), the housing body 24 is made of a synthetic resin , and has a generally rectangular box - like shape defined by the lower wall 26 , an upper wall 55 , disposed opposite to this lower wall 26 , a left wall 56 , a right wall 57 and a rear wall 58 . a lock member 61 , a pair of guide rails 62 with a larger height , a pair of bulge portions 63 and a pair of guide rails 64 with a smaller height are formed on the upper wall 55 , and also a pair of holes 65 for the front holder 28 ( see fig2 ) are formed in the upper wall 55 . the lock member 61 , the pair of guide rails 62 and the pair of guide rails 64 , formed on the upper wall 55 , extend in a forward - rearward direction in parallel relation to one another . the bulge portions 63 are formed on a rear portion of the upper wall 55 disposed adjacent to the rear wall 58 . the lock member 61 includes a strip - like elastic piece 66 which is integrally connected at one end thereof to a front portion of the upper wall 55 , and also is integrally connected at the other end thereof to the rear portion of the upper wall 55 . a projection 67 for engagement in the lock portion 35 ( see fig4 ) of the connector housing 32 ( see fig4 ) is formed on the elastic piece 66 intermediate opposite ends thereof . a pressing portion 68 is formed on the other end portion of the elastic piece 66 . the lock member 61 is of such a construction that the elastic piece 66 can be elastically deformed by pressing the pressing portion 68 . the pair of guide rails 62 , each having a piece - like configuration , are guided respectively by the guides 36 of the connector housing 32 ( see fig5 ), and a protector 69 for the lock member 61 is formed integrally with the rear ends of these guide rails . the protector 69 extends in the right - left direction of the upper wall 55 . this protector is formed into an arch - shape with respect to the guide rails 62 . the pair of bulge portions 63 , together with the guide rails 62 , protect the lock member 61 . the bulge portions 63 are integrally connected respectively to the rear ends of the guide rails 62 , and also to the rear ends of the guide rails 64 , respectively . the pair of guide rails 64 , each having a piece - like configuration , are guided respectively by the guides 37 of the connector housing 32 ( see fig5 ), and are formed integrally with the left wall 56 and the right wall 57 , respectively . the pair of holes 65 of a rectangular shape are provided respectively at the outer sides of the guide rails 62 ( that is , adjacent respectively to the left wall 56 and the right wall 57 ), and are formed through the front portion of the upper wall 55 . a hole 71 for the finger pad 29 and the front holder 28 ( see fig2 ) is formed in the left wall 56 . the hole 71 is formed through a front portion of the left wall 56 . the finger pad 29 is formed on the outer face of the left wall 56 at the rear portion thereof , and projects outwardly ( in the left direction ) from this outer face . the distal end ( outer face ) of the finger pad 29 in its projecting direction is disposed inwardly of an outer face of a left wall 72 of the connector housing 32 ( see fig4 or 5 ). when fitting the connector into the mating connector 22 ( see fig1 ), the finger is held on the finger pad 29 , and therefore the finger pad 29 will not engage the fitting portion 42 of the mating connector 22 ( see fig1 ). as described above for the left wall 56 , a hole 71 for the finger pad 29 and the front holder 28 ( see fig2 ) is formed in the right wall 57 . this hole 71 is formed through a front portion of the right wall 57 as described above for the left wall 56 . the finger pad 29 on the right wall 57 is formed on the outer face of this right wall 57 at the rear portion thereof , and projects outwardly ( in the right direction ) from this outer face . the distal end ( outer face ) of the finger pad 29 in its projecting direction is disposed inwardly of an outer face of a right wall 73 of the connector housing 32 ( see fig4 or fig5 ). a spacer mounting hole 76 and a front holder mounting hole 77 are formed in the lower wall 26 . a terminal receiving portion 78 is formed within the housing body 24 , and extends from the rear wall 58 to the front holder mounting hole 77 . the terminal receiving portion 78 has a plurality of terminal receiving chambers 79 . the spacer mounting hole 76 extends from an intermediate portion of the lower wall 26 to the rear portion thereof , and also extends from the lower wall 26 toward the upper wall 55 . the spacer mounting hole 76 communicates with the plurality of terminal receiving chambers 79 , and extends into the inner faces of the left and right walls 56 and 57 . body - side retaining portions 80 for the spacer 25 ( see fig1 ) are formed in inner faces of the spacer mounting hole 76 . the body - side retaining portions 80 include recesses 81 , respectively , which communicate with the spacer mounting hole 76 . one body - side retaining portion 80 is formed at a region including a rear portion of a left edge of the spacer mounting hole 76 and a rear edge of this hole 76 , whereas the other body - side retaining portion 80 is formed at a region including a rear portion of a right edge of the spacer mounting hole 76 and the rear edge of this hole 76 . each of the body - side retaining portions 80 includes a first retaining portion 82 ( see fig1 in which only one of them is shown ), and a second retaining portion 83 ( see fig1 in which only one of them is shown ). reference numerals 84 and 85 denote mold removal holes used for forming the first and second retaining portions 82 and 83 . the recesses 81 are formed in the inner face of the right and left walls 56 and 57 so as to oppose to the finger pads 29 , respectively . the recesses 81 are provided as widened groove portions extend from the opening edge ( that is , respectively from the left and right edges ) of the spacer mounting hole 76 in the direction of mounting of the spacer 25 ( that is , in the upward - downward direction ). part of the body - side retaining portions 80 are provided at the recess portions 81 , and therefore even when the connector is formed into a compact design , a sufficient retaining force for retaining the spacer 25 can be secured . the body - side retaining portions 80 may be formed entirely by the recess portions 81 . reference numerals 86 denote guide rails which are guided respectively by the guides 41 ( see fig5 ). reference numerals 87 denote recessed portions for the hinges 27 ( see fig1 ). the front holder mounting hole 77 is formed in the front portion of the lower wall 26 , and extends therefrom toward the upper wall 55 . the front holder mounting hole 77 communicates with the terminal receiving portion 78 , and extends into the inner faces of the left and right walls 56 and 57 . the front holder mounting hole 77 is formed to provide the open front side of the housing body 24 . the holes 65 , formed in the upper wall 55 , and the holes 71 , formed respectively in the left and right walls 56 and 57 , communicate with the front holder mounting hole 77 . the terminal receiving portion 78 includes the plurality of terminal receiving chambers 79 , a plurality of terminal inserting portions 90 , formed in that portion of the lower wall 26 lying between the spacer mounting hole 76 and the front holder mounting hole 77 , a plurality of terminal inserting portions 91 , formed in the rear wall 58 , and a partition wall 92 exposed to the spacer mounting hole 76 . the terminal receiving chambers 79 of a generally groove - shape extend in the forward - rearward direction , and are arranged in only one row in the right - left direction . the partition wall 92 is formed integrally with the terminal receiving chambers 79 . the partition wall 92 extends in the right - left direction so as to divide part of terminal receiving chambers 105 ( see fig1 and 14 ) in the spacer 25 ( see fig1 ). the plurality of terminal inserting portions 90 are arranged in two ( upper and lower ) rows , each row of terminal inserting portions 90 being arranged in the right - left direction . a lance 93 for engagement in the hole 48 ( see fig1 ) in the connection terminal 23 ( see fig1 ) is formed in a projected manner within each of the terminal inserting portions 90 . the lance 93 has elasticity , and serves to prevent the withdrawal of the connection terminal 23 ( see fig1 ). the plurality of terminal inserting portions 91 are arranged in two ( upper and lower ) rows , each row of terminal inserting portions 91 being arranged in the right - left direction . a partition wall 94 , separating the two rows from each other , is formed , and part of this partition wall 94 projects into the spacer mounting hole 76 . the partition wall 94 is spaced from the partition wall 92 , and when the spacer 25 ( see fig1 ) is attached to the connector , a partition wall 107 ( described later ) on the spacer 25 ( see fig1 ) is inserted into a space between the two partition walls 92 and 94 . next , the spacer 25 will be described with reference to fig1 to 17 . fig1 is a side view of the spacer , fig1 is a front view of the spacer , fig1 is a plan view of the spacer , fig1 is a bottom view of the spacer , fig1 is a rear view of the spacer , and fig1 is a cross - sectional view taken along the line c — c of fig1 . like the housing body 24 ( see fig6 to 11 ), the spacer 25 is made of a synthetic resin , and includes a lid portion 98 , conforming in shape to the opening of the spacer mounting hole 76 ( see fig7 ), side walls 99 , integrally formed respectively at opposite ( right and left ) ends of the lid portion 98 , a terminal receiving portion 100 , formed by inner faces of the lid portion 98 and the side walls 99 , and spacer - side retaining portions 101 formed respectively at rear portions of the side walls 99 . the front holder 28 is integrally connected to the band - like hinges 27 extending from a front portion of the lid portion 98 , and this front holder 28 is disposed perpendicularly to the lid portion 98 immediately after the spacer is molded ( the hinges 27 are bent when attaching the spacer to the connector ). of course , the front holder 28 is also made of the synthetic resin . in this embodiment , the front holder 28 is provided as an added function of the spacer 25 . of course , there can be provided the type of connector without the front holder ( as described above for the related example ). the side walls 99 have a length corresponding to the depth of the spacer mounting hole 76 ( see fig7 ), and these side walls 99 are so arranged as to be opposed respectively to the inner faces of the spacer mounting hole 76 ( see fig7 ). the terminal receiving portion 100 includes the plurality of terminal receiving chambers 105 , and partition walls 106 and 107 . the plurality of terminal receiving chambers 105 extend in the forward - rearward direction , and are arranged between the side walls 99 . these terminal receiving chambers 105 are arranged in one row . the partition walls 106 and 107 are spaced from each other by a distance corresponding to the dimension of the partition wall 92 ( see fig7 ) in the forward - rearward direction . these partition walls extend in the right - left direction . retaining portions 108 each for engagement with the shoulder portion 49 of the associated connection terminal 23 ( see fig3 ) are formed at the terminal receiving chambers 105 and the partition wall 106 . the retaining portion 108 and the lance 93 ( see fig9 ) serve to prevent the withdrawal of the connection terminal 23 ( see fig3 ). thus , the connection terminal 23 ( see fig3 ) is doubly retained by the retaining portion 108 and the lance 93 ( see fig9 ). the spacer - side retaining portions 101 can be engaged respectively with the body - side retaining portions 80 ( see fig1 ) so as to hold the spacer 25 in a provisionally - retained condition and a completely - retained condition . each of the spacer - side retaining portions 101 includes a provisional retainer 109 , a complete retainer 110 , a through hole 111 , and a slit 112 . since the spaces of the body - side retaining portions 80 ( see fig1 ) are secured , the spacer - side retaining portions 101 can maintain the sufficient retaining force . the provisional retainers 109 , as well as the slits 112 , are formed at distal end portions of the side walls 99 , respectively . as a result of formation of the slit 112 , the provisional retainer 109 has an arm - like configuration , and a retaining projection 113 is formed on and projects rearwardly from a distal end of each of the provisional retainers 109 . the provisional retainers 109 have sufficient elasticity . the complete retainers 110 , as well as the through holes 111 , are formed at proximal end portions of the side walls 99 , respectively . each of the complete retainers 110 has a retaining projection 114 which is formed on and projects rearwardly from an intermediate portion of the rear end of the side wall 99 . because of the provision of the through hole 111 , each of the complete retainers 110 can be elastically deformed to be displaced . in accordance with the arrangement of the recesses 81 ( see fig7 ), the outer faces of the spacer - side retaining portions 101 project outwardly from the outer faces of the side walls 99 , respectively . in accordance with the configuration of the body - side retaining portions 80 ( see fig7 ), each of the spacer - side retaining portions 101 slightly projects rearwardly . the front holder 28 is formed into a rectangular shape , and a plurality of terminal insertion ports 117 are formed in that side of this front holder which is to be opposed to the mating connector 22 ( see fig1 ), and are arranged in two ( upper and lower ) rows . terminal stoppers 118 are formed on that side of the front holder which is to be opposed to the terminal inserting portions 90 ( see fig8 ), and correspond respectively to the plurality of terminal insertion ports 117 . the terminal insertion ports 117 communicate with the terminal stoppers 118 , respectively . projections 119 , which can be engaged respectively in the holes 65 ( see fig6 ), projections 120 , which can be engaged respectively in the holes 71 ( see fig1 ), and ribs 121 , which can coincide respectively with the guide rails 86 , are formed on the outer peripheral face of the front holder 28 . next , an assembling operation for the connector 21 , comprising the connection terminals 23 , the housing body 24 and the spacer 25 , will be described . first , the front holder 28 is mounted in the front holder mounting hole 77 . the projections 120 on the front holder 28 are engaged respectively in the holes 71 , thereby preventing the withdrawal of the front holder . at this time , guide rails 125 ( see fig1 ), formed on the front holder 28 , are guided into groove - like guides 126 ( see fig7 ) formed in the inner faces of the front holder mounting hole 77 . then , the spacer 25 is provisionally retained in the spacer mounting hole 76 ( see fig1 ). in this mounting operation , each of the provisional retainers 109 is elastically deformed . when the provisional retainer 109 slides past the first retaining portion 82 , the provisional retainer 109 and the complete retainer 110 hold the first retaining portion 82 and the second retaining portion 83 therebetween . as a result , the spacer 25 is held in the provisionally - retained condition . in this condition , the connection terminals 23 can be inserted through the rear wall 58 . the connection terminals 23 , when thus inserted , are mounted and received in the terminal receiving chambers 79 , respectively . each of the connection terminals 23 is retained by the associated lance 93 , and therefore is prevented from being withdrawn from the rear wall 58 . also , the forward movement of the connection terminal 23 is prevented by the associated terminal stopper 118 on the front holder 28 . after all of the connection terminals 23 are mounted and received in the connector , the spacer 25 is completely retained . when each of the complete retainers 110 is elastically deformed , and slides past the second retaining portion 83 , the spacer 25 is completely engaged in the spacer mounting hole 76 ( see imaginary lines in fig1 ). the complete retainers 110 and the second retaining portions 83 prevent the disengagement of the spacer 25 . when the spacer 25 is thus completely retained , the retaining portions 108 on the spacer 25 are engaged respectively with the shoulder portions 49 of the connection terminals 23 , thereby doubly retaining these connection terminals 23 . therefore , the connection terminals 23 are positively prevented from being withdrawn from the rear wall 58 . thus , the sequential steps of the process of assembling the connector 21 are completed . as described above with reference to fig1 to 18 , the distance between the left wall 56 and the right wall 57 of the housing body 24 is made smaller by an amount , corresponding to the dimensions of the recesses 81 , as compared with the related construction . and besides , the spacer - side retaining portions 101 are formed respectively on those portions of the spacer 25 corresponding respectively to the recesses 81 , and therefore the spacer 25 , as well as the housing body 24 , is formed into a compact design . because of the provision of the recesses 81 , the spacer - side retaining portions 101 do not have a reduced thickness , and their retaining force for the spacer 25 is maintained generally at the same level as that obtained with the related construction . various modifications can be made without departing from the scope of the invention . for example , the connection terminals 23 can be replaced by male terminals . the invention can be applied to a housing body of the female type so that such male terminals can be received and retained in the housing body .