PURPOSE: To improve dimensional accuracy of the whole length of a workpiece by cutting a shaft part to a required length from the end of an umbrella part after grinding the outer periphery of the shaft part with a centerless grinder.

CONSTITUTION: A grinding wheel 2 is rotatingly-driven at a high speed through the first motor and the first rotating shaft. A regulating wheel 3 is rotatingly- driven at a lower speed than the grinding wheel 2 in the same direction as the grinding wheel 2. As a result, while the workpiece 1 is being rotated in the opposite direction to the grinding wheel 2 on a workpiece supporting plate, the periphery of its shaft part is ground. The workpiece 1 is transferred to a cutting machine and the shaft part 1a is cut to a required length from the end of the umbrella part 1b. The workpiece 1 which is being processed is pressed against a loader head 18 and positioned exactly.