PURPOSE: To polish cutting tool, etc. accurately and easily by moving reciprocatedly a stone linearly on the same horizontal plan by repeating reversal rotation of an ultrasonic wave motor.

CONSTITUTION: A grinding wheel stand 3 is arranged on a frame 1 so that it can be moved reciprocatedly linearly through a guide means 2, a linear rack 7 is mounted on the grinding wheel stand 3, an ultrasonic wave motor 8 is mounted on the frame 1, and a pinion 9 mounted on its output shaft is engaged with the rack 7. Also the drive device 11 of the ultrasonic wave motor 8 is so structured that the rotational direction of the motor is switched over by a detection signal from a position switchover sensor located at the reciprocating switchover position of the wheel stand 3.