An actuator (100, 100A, 100B) comprising: a movable body (120, 120A, 120B) including a cylindrical magnet portion (123, 123A, 123B) having on a circumferential surface thereof alternating N pole faces and S pole faces along a circumferential direction thereof; and an immovable body (110, 110A, 110B) including pole tooth faces (115b, 1155; 116b, 1165) arranged along the circumferential direction so as to face the circumferential surface of the magnet portion (123, 123A, 123B), the number of the pole tooth faces (115b, 1155; 116b, 1165) being equal to the number of the N pole faces and the S pole faces, and a coil (114b, 1142) configured to excite the pole tooth faces (115b, 1155; 116b, 1165), a torsion coil spring configured to support the movable body (120, 120A, 120B) to the immovable body (110, 110A, 110B) in a movable manner about a rotary shaft (122,122B) that is a part of the movable body (120, 120A, 120B), wherein the torsion coil spring is configured to bias the movable body (120, 120A, 120B) to a neutral position for rotation of the movable body (120, 120A, 120B), the neutral position being a position at which center positions of the pole tooth faces (115b, 1155; 116b, 1165) in the circumferential direction and boundary positions between the pole faces of the magnet portion (123, 123A, 123B) face each other the coil (114b, 1142) is configured to receive an alternating current of a fre quency substantially equal to a resonance frequency of the movable body (120, 120 A, 120B), the resonance frequency being determined by an inertia of the movable body (120, 120A, 120B) and a spring constant in a torsion direction of the torsion coil spring, and to excite the pole tooth faces (115b, 1155; 116b, 1165) to have alternately different polarities in the circumferential direction, and one end of the torsion coil spring is fixed to one end of the rotary shaft (122, 122B) of the movable body (120, 120A, 120B), the other end of the torsion coil spring is fixed to the immovable body (110, 110A, 110B), and the torsion coil spring is placed such that a central axis of the torsion direction coincides a center of the rotary shaft (122, 122B), and is configured to support the movable body (120, 120A, 120B) to the immovable body (110, 110A, 110B) such that the movable body (120, 120A, 120B) vibrates at the resonance frequency of the movable body (120, 120A, 120B). a movable body (120, 120A, 120B) including a cylindrical magnet portion (123, 123A, 123B) having on a circumferential surface thereof alternating N pole faces and S pole faces along a circumferential direction thereof; and an immovable body (110, 110A, 110B) including pole tooth faces (115b, 1155; 116b, 1165) arranged along the circumferential direction so as to face the circumferential surface of the magnet portion (123, 123A, 123B), the number of the pole tooth faces (115b, 1155; 116b, 1165) being equal to the number of the N pole faces and the S pole faces, and a coil (114b, 1142) configured to excite the pole tooth faces (115b, 1155; 116b, 1165), a torsion coil spring configured to support the movable body (120, 120A, 120B) to the immovable body (110, 110A, 110B) in a movable manner about a rotary shaft (122,122B) that is a part of the movable body (120, 120A, 120B), wherein the torsion coil spring is configured to bias the movable body (120, 120A, 120B) to a neutral position for rotation of the movable body (120, 120A, 120B), the neutral position being a position at which center positions of the pole tooth faces (115b, 1155; 116b, 1165) in the circumferential direction and boundary positions between the pole faces of the magnet portion (123, 123A, 123B) face each other the coil (114b, 1142) is configured to receive an alternating current of a fre quency substantially equal to a resonance frequency of the movable body (120, 120 A, 120B), the resonance frequency being determined by an inertia of the movable body (120, 120A, 120B) and a spring constant in a torsion direction of the torsion coil spring, and to excite the pole tooth faces (115b, 1155; 116b, 1165) to have alternately different polarities in the circumferential direction, and one end of the torsion coil spring is fixed to one end of the rotary shaft (122, 122B) of the movable body (120, 120A, 120B), the other end of the torsion coil spring is fixed to the immovable body (110, 110A, 110B), and the torsion coil spring is placed such that a central axis of the torsion direction coincides a center of the rotary shaft (122, 122B), and is configured to support the movable body (120, 120A, 120B) to the immovable body (110, 110A, 110B) such that the movable body (120, 120A, 120B) vibrates at the resonance frequency of the movable body (120, 120A, 120B).