To realize the high grinding accuracy of a work W.

When the work W is fed in the rotational direction of a grinding wheel 11 via a carrier 13 and ground, the grinding of the work W is completed at the center height angle δ>0°. Since the work W is not ground at the center height angle δ=0°, the circularity can be improved while suppressing the harmful effect of the distorted regular circle of odd-numbered angle to a minimum.