PURPOSE: To improve the work efficiency by providing a control device issuing a command to a rest device according to journal section grinding or cam section grinding to change the pressing margin at the time of grinding so that journal section grinding and cam section can be performed via a stepless exchange with one machine.

CONSTITUTION: When a journal section WJ is to be ground, a rest device 20 is first-step-feed-controlled into contact with the journal section WJ by a control device 53 with the pressing margin corresponding to its grinding resistance. When a cam section WC is to be ground, the pressing margin is changed to that corresponding to its grinding resistance by the control device 52, and the rest device 20 is second-step-feed-controlled into contact with the journal section WJ. The journal section WJ and the cam section WC can be efficiently ground via a stepless exchange with one machine.