An actuator includes: a frame; first members at each end of the frame along a first axis making the frame rotatable thereabout; second members supporting each end of a movable plate against the frame along a second axis making the movable plate rotatable thereabout; first magnets with poles interposing the first axis; a second magnet with poles interposing the first axis; a coil generating a magnetic force acting on the first and second magnets; and a voltage source applying a voltage to the coil. The first and second magnets have an angle of 30-60 degrees to the first axis, and identical magnetic pole directions. The voltage source includes first and second voltage generators generating first and second voltages of first and second frequencies, and a voltage superimposer. The movable plate is rotated about the first and second axes at the first and second frequencies by the superimposed voltages.