On an outer surface of an electromagnetic valve body, a manual operation element is provided slidably horizontally, and a slide member is provided slidably in a direction orthogonal to a sliding direction of the manual operation element. The slide member is movable to a lock position and a non-lock position. At the lock position, the slide member is retained by the manual operation element to lock the manual operation element at a non-switch position. At the non-lock position, the slide member unlocks the manual operation element to allow the manual operation element to move toward a switch position.