PURPOSE: To provide the control system for the piezoelectric actuator which can precisely control the displacement quantity of the piezoelectric actuator to a desired displacement quantity without overshooting.

CONSTITUTION: The difference between an input control voltage corresponding to the desired displacement quantity and the output voltage of an amplifier 3 which amplifies the output of a sensor 2 is amplified by a differential amplifier 4. The output voltage of the differential amplifier 4 is converted by a power amplifier 5 into a current, which flows to the piezoelectric actuator 1. The current, thus, flows to the piezoelectric actuator 1 and electric charges are charged in the piezoelectric actuator 1. According to the accumulated charges, the piezoelectric actuator 1 is displaced. The piezoelectric actuator 1 is displaced until the difference between the input control voltage and the output voltage of the amplifier 3 is eliminated.