To prevent the deterioration of the service life of a thrust ball bearing by eliminating inconvenience such as increase of bearing when a ball contacts with the central projecting part side of a groove recessed part in setting a diameter of a groove bottom pitch circle of orbit grooves smaller than eccentric quantity of turning motion in the thrust ball bearing formed by interposing the ball between the opposed orbit grooves and forming the annular orbit grooves at a constant pitch in opposed positions of a pair of bearing rings relatively making eccentric turning motion.

In this thrust ball bearing, and in a shape of orbit grooves 3 of a bearing ring 1, the groove depth (a) of the outer peripheral end 14 of a groove recessed part 13 is set same as the groove depth (b) of the inner peripheral end 14' of the groove recessed part 13 or larger than this. A cross-sectional shape of the groove recessed part 13 is constituted in a shape different in curvature in the same angle θ between normals viewed from one point P on the normals stood on the groove bottom (c) of the groove recessed part 13.