To obtain a piezoelectric actuator which has a large displacement and is applicable in a wide range of use.

This piezoelectric actuator is composed of a nearly U-shaped metal plate 1 with two arms 2 and 3 and piezoelectric ceramic elements 10 and 11 which are each deposited on the one surfaces of the arms 2 and 3 so as to be opposite to each other in polarization axis. The tip of the arm 2 of the metal plate 1 serves as a stationary end, the tip of the other arm 3 serves as a displacement end, and an electric field of the same direction is applied to the piezoelectric ceramic elements 10 and 11, thereby bending the arms 2 and 3 of the metal plate 1 opposite in phase.