To provide a ball bearing not producing wear of an engaging claw at a time of assembly of a synthetic resin retainer and not producing rattle of a retainer easily.
In the ball bearing including the synthetic resin retainer 4 having hemispherical pockets 7 storing a ball 3 formed on facing surfaces of two annular bodies 6a, 6b facing in an axial direction at even intervals in a circumference direction, provided with the engaging claws 9 projecting in an axial direction between adjacent pockets 7, 7 of one annular body 6a, having engaging holes 10 in which the engaging claws 9 are inserted formed between adjacent pockets 7, 7 of another annular body 6b, and joining the annular bodies 6a, 6b by engaging the engaging claws 9 inserted in the engaging hole 10 with the annular body 6b, and retaining the balls 3 between an inner ring 1 and an outer ring 2 by the synthetic resin retainer 4, an expanding slot 11 is formed on a tip of the engaging claws 9.
Higashio Masahiro
Torii Kazuhisa