In an image forming apparatus, a cartridge is detachably mounted in a frame, the cartridge being located at a mounted position in the frame when the image forming apparatus is packaged with the cartridge mounted in the frame, the mounted position being defined in the frame in a mounting direction, in which the cartridge moves relative to the frame so as to be mounted in the frame. An attachment member is detachably attached to the cartridge when the image forming apparatus is packaged with the cartridge mounted in the frame. A restricting mechanism restricts mounting of the cartridge to the mounted position if the attachment member is attached to the cartridge, the restricting mechanism restricting the mounting of the cartridge at a position upstream of the mounted position in the mounting direction.