A stationary core is in an exciting coil. A yoke covers an outer periphery and an axial end of the exciting coil to form a magnetic circuit and has an opening portion. The movable core faces the stationary core through the opening portion and is attracted toward the stationary core on energization of the exciting coil. A return spring urges the movable core against the attraction direction. A first gap is formed between the stationary core and the movable core on deenergization of the exciting coil. A second gap is formed between the yoke and the movable core on deenergization of the exciting coil. The second gap allows the yoke and the movable core to generate an attractive force therebetween on energization of the exciting coil. The return spring is made of a magnetic material to magnetically bridge the first gap or the second gap.