An image forming apparatus is provided. An image forming apparatus includes: a drum cartridge having a photosensitive drum; a developing cartridge configured to be movably attached to the drum cartridge, the developing cartridge having: a developing roller; a bearing member; and a developing drive input member; and a spacing member for pressing against a predetermined portion of the developing cartridge and moving the developing cartridge such that the developing roller is spaced apart from the photosensitive drum, wherein the drum cartridge has an abutment portion with which the bearing member is brought into abutment, and wherein a straight line which connects the abutment portion with a center of a rotational axis of the developing drive input member extends substantially in the same direction as a connecting or disconnecting direction of the developing roller to or from the photosensitive drum.