There is provided a small and inexpensive actuator which has a simple structure and can obtain a large displacement. When voltage is applied to electrodes 2a and 2b formed on an inner circumferential surface and an outer circumferential surface of a piezoelectric ceramic 1 wound like a coil, deformation occurs in such a direction that an inner circumferential side of the piezoelectric ceramic 1 wound like the coil is contracted, and an outer circumferential side is expanded. Accordingly, if one end portion of the piezoelectric ceramic 1 formed into the coil shape is fixed, the other end portion is rotated in accordance with the deformation of contracting the diameter of this coil.