A self-sensing actuator using piezoelectric two films with different thickness and area, which are closely installed on one surface of general curved structures and are treated as two capacitors in the active RC bridge circuit, is proposed from the view-point of simplification of hardware aspects of devices toward the realization of smart structures. It is first implied that this device is effective in the following points, i.e., 1) compensation of ME noises, 2) ability of obtaining high gain feedback and enough control power and 3) compensation of temprature for pyroelectric effect. Then, vibration control effects are estimated by theoretical analyses of free vibration response and harmonic steady -state response of a cantilever which is an example of fundamental flexible structures, and the guideline for constructing control circuit is shown. Finally, the validity of proposed self-sensing actuator scheme is verified by conducting the experiment of free vibration response of a cantilever.