A lever is provided in a photosensitive member frame of a photosensitive member cartridge that accommodates a developing cartridge in a cartridge accommodating portion. The lever is engaged with an engaging shaft of the developing cartridge, and is movable between a contact position and a separation position. When the lever is in the contact position, a developing roller and a photosensitive drum make contact with each other, and when the lever is in the separation position, the developing roller and the photosensitive drum are separated.