An interlock switch includes a switch mechanism. The switch mechanism includes a switch having an arm as an actuator, a holding member to which the switch is fastened by a rocking mechanism, the holding member being rotatably disposed in an apparatus body, one pressing member which presses the arm from the arm side, other pressing member which presses the holding member from the side opposite to the arm side, one elastic member which regulates the ON position of the switch in a releasing direction in arm-side view, and other elastic member which applies a force to the switch in a direction in which the one pressing member comes close to the switch. The switch is turned on when the one pressing member presses the arm from the arm side and the other pressing member presses the holding member from the side opposite to the arm side.