PURPOSE: To prevent tempering, quenching crack or the like of a workpiece and facilitate setting of a grinding wheel and pouring of grinding water.

CONSTITUTION: In a grinding method of workpiece collar, an inside grinding surface (k) of an outside collar 13a of an external wheel 13 which is rotated while being held by a backing plate 11 and a shoe 12 is ground by a conical working surface (s) provided on a quill 14 side of a grinding wheel 15 rotating around the quill 14, and in this method, the conical working surface (s) and the inside grinding surface (k) are in linear contact with each other by inclining the quill 14.