Actuator and electric toothbrush utilizing same

An actuator having:

• an outer yoke having inner wall planes that are placed a predetermined interval apart opposing each other;
• a permanent magnet that is placed to oppose the opposing inner wall planes over an air gap and that has different magnetic pole planes that oppose the inner wall planes respectively;
• and
• a coil that is placed in the air gap and surrounds the permanent magnet, the actuator comprising:
• a fixed body that has one of the permanent magnent and the coil;
• a movable body that has the other one of the permanent magnet and the coil and that has an output shaft that is perpendicular to both a direction in which the magnetic pole planes and the inner wall planes oppose each other and an axial direction of winding of the coil;
• an alternating current supplying section that supplies an alternating current of approximately a same frequency as a resonance frequency of the movable body to the coil;
• and
• a linear elastic member that has its one end fixed to the fixed body and the other end fixed to the movable body, and that supports the movable body on the fixed body to be able to rotate about an axis along the output shaft.