An electromagnetic actuator has a rotor and a stator around which coils are wound to face portions of an outer surface of the rotor. The stator is C-shaped, the rotor is arranged so that a rotation axis thereof is existent in a space surrounded by the stator, and both ends of the stator are respectively formed within a range from 15 to 90 degrees from a virtual base line with respect to the rotation axis serving as a center, when the virtual base line is set to run a center of the rotation axis and separate the stator into left and right.