PURPOSE: To obtain a large displacement with low voltage, by forming a first and a second piezoelectric units in a bimorph shape, and by setting the oscillating directions to be the directions of the thicknesses.

CONSTITUTION: One end of a first piezoelectric unit 1 is fixed, and the other end is oscillated vertically in the direction of the thickness. One end of a second piezoelectric unit 2 is connected to the other end of the first piezoelectric unit 1, and the other end of the unit 2 is oscillated vertically in the direction of the thickness. A converting section 3 is connected to the other end of the second piezoelectric unit 2, and vertical oscillation is converted to horizontal oscillation. A rotary body 4 is made to come in pressure contact with the converting section 3. Voltage having the mutual phase difference of 90° is applied to the first and second piezoelectric units 1, 2.