PURPOSE: To aim at miniaturizing a part grinding device by pressing a part against a grindstone after the part is rotated by a predetermined angle by a zeneva means coaxial with a cam while the part is moved away from the grindstone by rotating a cam means so that the part is extended and retracted and is rotated only one drive source.

CONSTITUTION: A drive source 16 rotates a grindstone 18 so as to a gear 48 at the lower end of the shaft of the grind stone is rotated at a reduced speed through a mission 42, and therefore, a gear 62 having a diameter of 1/4 of that of the gear 48 is rotated. The rotation of the shaft of the gear 46 is transmitted through a universal joint 92 to a shaft 90 formed therein with a cam member 100 and a clamp member 106. Therefore, the rotation of the cam member 100 causes a slide table 22 to move to and away from the grindstone 18. A zeneva gear 130 is rotatably provided on the slide table 22, and a workpiece W is planted. The rotation of the clamp member 106 causes a clamp pin to rotate the zeneva gear 130 at predetermined intervals so that the angle of the workpiece W may be changed. Simultaneously, the workpiece W is engaged to disengaged from the grindstone 18 due to the reciprocating motion of the slide table 22.