In a solenoid, a coil is energized in a state where movement of a plunger toward the inside of a yoke is stopped. Accordingly, when the coil is energized, it suffice that movement of the plunger toward the outside of the yoke is inhibited by a magnetic force, and it is not necessary to move the plunger into the yoke by the magnetic force. Therefore, it is not necessary that a force moving the plunger toward the inside of the yoke is increased by a conventional core. Accordingly, the conventional core is not assembled in a frame, so that number of components can be decreased so as to reduce the cost.