A straddled vehicle starter motor (10, 210) configured to start up an engine mounted to a straddled vehicle, the straddled vehicle starter motor (10, 210) comprising: a rotor configured to be rotatable, and including a winding (9, 209), a core with the winding (9, 209) wound thereon, and a commutator electrically connected to the winding (9, 209); a brush (22, 23) configured to contact the commutator to cause a current to flow in the rotor, the brush (22, 23) having the position thereof fixed with respect to a rotation direction of the rotor; and a movable permanent magnet arranged so as to oppose the core with a gap therebetween and so as to be movable in a circumferential direction of the rotor independently of the rotor within an angle range including a retarded angle position and an advanced angle position, the retarded angle position being an angle position where the movable permanent magnet is displaced in a retarded angle direction relative to the brush (22, 23), the advanced angle position being an angle position where the movable permanent magnet is displaced in an advanced angle direction relative to the brush (22, 23) when compared to the retarded angle position and where a higher torque is caused in the rotor than a torque caused in the retarded angle position, a magnet moving unit configured to locate the movable permanent magnet in the advanced angle position at a time point when the rotor starts rotation upon a current supply to the rotor, and to move the movable permanent magnet in the retarded angle direction to the retarded angle position within a period in which the rotor is rotating with a current supplied to the rotor and in which the rotation speed of the rotor continuously increases after the rotor starts rotation, wherein the magnet moving unit includes an elastic member configured to bias the movable permanent magnet in the retarded angle direction with an elastic force, an actuator configured to move the movable permanent magnet with electric power, or a motor. a rotor configured to be rotatable, and including a winding (9, 209), a core with the winding (9, 209) wound thereon, and a commutator electrically connected to the winding (9, 209); a brush (22, 23) configured to contact the commutator to cause a current to flow in the rotor, the brush (22, 23) having the position thereof fixed with respect to a rotation direction of the rotor; and a movable permanent magnet arranged so as to oppose the core with a gap therebetween and so as to be movable in a circumferential direction of the rotor independently of the rotor within an angle range including a retarded angle position and an advanced angle position, the retarded angle position being an angle position where the movable permanent magnet is displaced in a retarded angle direction relative to the brush (22, 23), the advanced angle position being an angle position where the movable permanent magnet is displaced in an advanced angle direction relative to the brush (22, 23) when compared to the retarded angle position and where a higher torque is caused in the rotor than a torque caused in the retarded angle position, a magnet moving unit configured to locate the movable permanent magnet in the advanced angle position at a time point when the rotor starts rotation upon a current supply to the rotor, and to move the movable permanent magnet in the retarded angle direction to the retarded angle position within a period in which the rotor is rotating with a current supplied to the rotor and in which the rotation speed of the rotor continuously increases after the rotor starts rotation, wherein the magnet moving unit includes an elastic member configured to bias the movable permanent magnet in the retarded angle direction with an elastic force, an actuator configured to move the movable permanent magnet with electric power, or a motor.