PURPOSE: To prevent the bending of a cutter in the working for a workpiece by a cutter and smooth working.

CONSTITUTION: An ultrasonic type cutter 1 is constituted of being equipped with a ultrasonic wave generator 3 equipped with ceramic vibrator elements 10 and 12, horn 7, etc., case 2 having an ultrasonic wave generator 3 accommodated, and a cutter 4 installed at the top end part of the case so as to project from the top end of the case 2. The cutter 4 is constituted of a cutter body part 4a and a pair of cutter installation parts 4b and 4c, and the cutter 4 is installed on a cutter holder 15 through the cutter installation parts 4b and 4c, and the cutter holder 15 having the cutter 4 installed is installed at the small diameter part 7a of the horn 7.