To provide a solenoid with high straightness of a movable iron core.SOLUTION: In a solenoid 1 that drives a movable core 3 toward a fixed core 4 against urging force of a spring 5 by the magnetic action when a coil 2 is energized, the movable iron core 3 includes a shaft portion 31 protruding in the axial direction, the fixed core 4 is formed with a shaft hole 4a through which the shaft portion 31 is inserted, and the spring 5 is arranged in contact with the shaft portion 31 inserted into the shaft hole 4a.SELECTED DRAWING: Figure 1