A rotary microactuator is optimally designed so that the interval between two electrodes, which are a rotor (400) and a stator (300), is constant regardless of a distance from the central axis of the rotor. Thus, a parallel-plate configuration can generate a maximum driving force, and also can widen a driving range. In particular, in a rotary microactuator using parallel-plate configuration electrodes, the electrodes are optimally designed so that the interval between the electrodes remains constant regardless the radius by tilting the electrodes or by zigzagging the electrodes. Therefore, a driving force for a given area can be maximized.