PROBLEM TO BE SOLVED: To fully compensate waveform accuracy of a driving signal for driving an actuator consisting of a capacitive load.SOLUTION: A difference signal Diff of a driving waveform signal WCOM and a feedback signal Ref is subjected to pulse modulation, a modulation signal PWM is subjected to power amplification by a digital power amplification circuit 27, a power amplification modulation signal APWM is smoothed by a smoothing filter 28, and a driving signal COM is applied to an actuator 19 consisting of a capacitive load such as a piezoelectric element. In that case, the driving signal COM itself is fed back to a subtraction unit 25 as a first feedback signal, a phase of the driving signal COM is advanced, and the driving signal COM is fed back to the subtraction unit as a second feedback signal. At that time, a grounding resistor R as a current detector is connected to a capacitor C of the smoothing filter 28, and output of the grounding resistor R as the current detector is fed back to the subtraction unit 25 as the second feedback signal.
