In a synthetic resin retainer formed by joining together two annular members by engaging claws of each annular member in engaging holes of the annular member, each of the two annular members 1 has a plurality of hemispherical pockets 4 formed in a side surface thereof to be brought into abutment with the side surface of the other annular member at circumferentially equal intervals. Joint portions are provided between the adjacent pockets 4, and each is provided with an engaging hole 5 and an engaging claw 6. The engaging claws 6 and engaging holes 5 are configured such that gaps are present between the engaging claws 6 and the engaging holes 5 in the initial stage of assembly of the retainer, and the gaps decrease to zero or less upon completion of the assembly of the retainer, thereby preventing wear of the engaging portions of the engaging claws for joining the annular members together.