PURPOSE: To reduce the number of parts for the horizontal feed mechanism of a turn table and the vertical feed mechanism of a grinding wheel so as to make the whole device low-priced and compact.

CONSTITUTION: A frame 2 is provided with a moving body 4 in the horizontally movable state. A turntable 5 provided with a chuck and a chuck wrench 8 is disposed on the moving body 4, and the turntable 5 is rotated around a vertical axis by a table driving motor 10. A grinding wheel driving motor 32 is installed on an elevated body 31 energized upward by a spring 39 so as to rotate a grinding wheel 34. The horizontal feed mechanism of the turn table 5 is formed of a horizontal feed cam 12 formed at the turntable 5, and a cam follower 21 provided at the frame 2. The vertical feed mechanism of the grinding wheel 34 is formed of a vertical feed cam 16 formed at the turntable 5, a cam follower 43 provided at the moving body 4, an engaging element 52 engaged with the elevated body 31, and the like. The vertical feed quantity of the grinding wheel 34 is adjusted by an adjusting knob 57.