An actuator includes a rotor, a stator containing the rotor, and a bearing to support the rotor to be rotatable with respect to the stator about the central axis of the rotor and an axis perpendicular to the central axis. The rotor includes rotor central magnetic poles, a rotor upper magnetic pole, and a rotor lower magnetic pole. The stator includes stator central magnetic poles larger in number than the rotor central magnetic poles, stator upper magnetic poles, stator lower magnetic poles, central coils to appropriately magnetize the stator central magnetic poles, upper coils to appropriately magnetize the stator upper magnetic poles, and lower coils to appropriately magnetize the stator lower magnetic poles. The length of each stator central magnetic pole along a central axis of the stator is larger than a length of each rotor central magnetic pole along the central axis of the rotor.