A door is held in an open condition by locking a stopper member whose one end is turnably supported by an apparatus body. The stopper member is composed of a base member having a project portion and a turning shaft portion supported by a printer body, and a reinforcing member. The reinforcing member is joined with the base member by a joining mechanism such that, in a case when a force of predetermined magnitude is applied to the door in opening the door, the base member is broken and the reinforcing member holds the door by supporting the project portion and the turning shaft portion of the broken base member.