the bearing of the present invention comprises a hub 110 for driving recording media ; a sleeve 120 for rotatably support the hub 110 to define a hydrodynamic pressure generating space 110 a between the hub 110 and the sleeve 120 , the sleeve 120 being formed with a fluid outlet 125 b through which the fluid passes at the predetermined position ; a plurality of recesses 125 a for generating hydrodynamic pressure , the recesses 125 being formed on at least one of the hub 110 and the sleeve 120 to be opened toward the hydrodynamic pressure generating space 110 a ; and a fluid circulating member 130 for circulating the fluid out - flowing from the fluid outlet 125 b to the hydrodynamic pressure generating space 110 a , the member 130 being fixedly combined with the hub 110 to slidably support the sleeve 120 .