PURPOSE: To realize the inner ring of a constant velocity universal joint which has no dispersion in working dimensions of its outer peripheral spherical surface.

CONSTITUTION: As an annular projection 32 having an outer peripheral cylindrical surface 30 which is continuous in the circumferential direction is projected in the direction of the shaft center concentrically with the center hole 28 in its opening edge part, when the outer peripheral cylindrical surface 30 of the annular projection 32 is ground by a grinding wheel 16 for grinding the cylindrical surface 30 simultaneously with the outer peripheral spherical surface 24, the working dimensions of the outer peripheral spherical surface 24 can be estimated by measuring the diameter dimension of the outer peripheral cylindrical surface 30 of the annular projection 32, and the grinding depth of cut of the outer peripheral spherical surface 24 can be controlled according to the dimension. As the outer peripheral cylindrical surface 30 of the annular projection 32 is continuous in the circumferential direction, the need of signal processing for removal from a measuring signal can be eliminated by making a signal corresponding to a recessed groove 26 invalid so as to obtain correct values of dimensions and eliminate intermittent vibration caused when a measuring probe enters the recessed groove 26. Thus, the measurement value itself is stabilized to reduce dispersion in working dimensions of the outer peripheral spherical surface 24, so that the correct shape of the outer peripheral spherical surface 24 can be obtained.