PURPOSE: To enable the polishing of the inner peripheral face in a small diameter simply and highly accurately, by generating ultrasonic vibration in the circumferential direction by an exciting means and making a polishing means provided at the tip of a bar body subjected to a high frequency vibration in the circumferential direction after amplifying the vibration by an amplifier.

CONSTITUTION: The title device is equipped with an exciting mean 2 which generates untrasonic vibration in the circumferential direction by electifying the alternating current in the specific frequency, an amplifying body 3 which amplifies the ultrasonic vibration transmitted from the exciting means 2, having the shape that one end is fixed to the exciting means 2 and the other end is tapered toward the tip side as well, flange 1 which fixes the vibration node of this amplifying body 3 and also stores the exciting mean 2 at the internal part and a polishing mean 5 provided at the part of the vibration flat of the bar body fixed to the tip of the amplifying body 3. Namely the polishing mean 5 is vibrated with the ultrasonic vibration being transmitted to the polishing mean 5 of the bar body tip after its amplifying by the amplifying body 3. Consequently polishing can be performed easily and with high accuracy at even the specially back part, etc., of the hole inner peripheral face.