A solenoid, comprising: a coil; a first movable iron core and a second movable iron core that are attracted in a direction away from each other by energizing the coil; a biasing member that biases the first movable iron core toward the second movable iron core; a first regulation member that restricts approach of the first movable iron core and the second movable iron core; and a first fixed iron core and a second fixed iron core that are arranged with a predetermined distance between the first fixed iron core and the second fixed iron core, wherein the first movable iron core and the second movable iron core have a cylindrical shape with a bottom, and are disposed between the first fixed iron core and the second fixed iron core so as to be able to approach or be separated from the first fixed iron core and the second fixed iron core, respectively, and bottom portions of the first movable iron core and the second movable iron core face the second fixed iron core, the first movable iron core is movably inserted into an inside of the second movable iron core, and is disposed on a side of the second movable iron core facing the first fixed iron core to be attracted to the first fixed iron core by energizing the coil, the biasing member is a coil spring, and is inserted into an inside of the first movable iron core to be interposed between the bottom portion of the first movable iron core and the first fixed iron core, and the second movable iron core is disposed on a side of the first movable iron core facing the second fixed iron core to be attracted to the second fixed iron core by energizing the coil. a coil; a first movable iron core and a second movable iron core that are attracted in a direction away from each other by energizing the coil; a biasing member that biases the first movable iron core toward the second movable iron core; a first regulation member that restricts approach of the first movable iron core and the second movable iron core; and a first fixed iron core and a second fixed iron core that are arranged with a predetermined distance between the first fixed iron core and the second fixed iron core, wherein the first movable iron core and the second movable iron core have a cylindrical shape with a bottom, and are disposed between the first fixed iron core and the second fixed iron core so as to be able to approach or be separated from the first fixed iron core and the second fixed iron core, respectively, and bottom portions of the first movable iron core and the second movable iron core face the second fixed iron core, the first movable iron core is movably inserted into an inside of the second movable iron core, and is disposed on a side of the second movable iron core facing the first fixed iron core to be attracted to the first fixed iron core by energizing the coil, the biasing member is a coil spring, and is inserted into an inside of the first movable iron core to be interposed between the bottom portion of the first movable iron core and the first fixed iron core, and the second movable iron core is disposed on a side of the first movable iron core facing the second fixed iron core to be attracted to the second fixed iron core by energizing the coil.