now referring to fig1 fig2 and fig3 showing the first embodiment of the invention , a numeral number 1 designates a case for a small - sized electric motor . two arched permanent magnets 2 are disposed on an inner periphery of a cylindrical portion 1a of the case 1 . a symbol a designates a shoulder portion provided at the end of the inner periphery of the cylindrical portion 1a . the shoulder a abuts the magnets at one of their axial ends . a symbol d designates a convex portion which is protruded between the two magnets 2 from the cylindrical portion 1a in the radial direction . a symbol c designates a projection which is provided on the convex portion d by cutting and pressing in a circular direction of the cylindrical portion 1a . the projection c urges the ends of magnets in the circular direction . another projection b is provided on the cylindrical portion 1a by cutting and pressing , and this projection b urges the magnet 2 to the shoulder a . in a construction as aforementioned , the shoulder a , the first projection c , the second projection b and the convex portion d are easily formed unitary with the cylindrical portion by a pressing process . the magnet 2 is disposed on the inner periphery of the cylindrical portion 1a of the case 1 and between the shoulder a and the second projection b . the magnet 2 is put into the case 1 until it abuts the shoulder a provided in the cylindrical portion 1a . the spring action of the projection b urges the magnet 2 to the shoulder a , whereby the magnet 2 is secured in its correct axial position . at the same time the magnet 2 is held between the first projection c and the side of another convex portion d , whereby the magnet 2 is secured stably in the inner periphery of the cylindrical portion 1a by the spring action of the first projection c . the first projection c may be substituted for a projection c &# 39 ; shown in fig4 and 6 . as shown in these figures , the projection c &# 39 ; is formed by cutting both sides of the projection c &# 39 ;, while the projection c is formed by cutting three sides thereof . the projection c &# 39 ; and the convex portion d hold the magnet 2 stably therebetween and against the inner periphery of the cylindrical portion 1a in the same manner as described in fig1 , and 3 . though the second projection b serves to restrict movement of the magnet 2 in the axial direction , the magnet 2 can be restricted in the axial direction by the first projection c or c &# 39 ; and the convex portion d alone without using the second projection b . therefore , in this case the second projection b can be eliminated .