To obtain an actuator that drives a damper using and controlling the rectified waveform of a DC motor.

This actuator for driving a damper uses the rectified waveform 9 of a DC motor 1 to control and drive the motor 1. The waveform 8 of the motor 1, that is built in the actuator, is taken out to control and drive the motor 1. Power is transmitted to an output gear 2 via a speed reducing mechanism, and a damper 6 is made arbitrarily controllable with a lever 5 so that a low-cost system mechanism is obtained.