In an adder circuit, a sine wave is added to a compensation signal which is generated based on a position detection signal of a member to be driven and for compensating a position of a lens which is the member to be driven. An absolute value integrating circuit integrates absolute values of signals before and after the adder circuit adds the sine wave. The two obtained integrated values are compared by a comparator circuit, and a gain adjusting circuit adjusts a gain of an amplifier which amplifies the compensation signal so that the two integrated values are equal to each other.