PURPOSE: To provide possibility of proceeding to the subsequent process with finish grinding with the processing jig held in fitting as it is by carrying out the basic processiing with the work piece set in the same processing device.

CONSTITUTION: A work piece 9 is set in a work set device 10, on which a processing jig 17 is fitted to perform a specified basic processing. After this basic processing is completed, a change-over device 24 shall change over 24 the mechanism to the finish grinding device from said basic processing device. A grinding element is interpose between the work and jig with the work set as it is, and at least one of these two is put in oscillation at a specified cycle and dimension to proceed directly to finish grindings 19, 20.