An image forming apparatus includes a main body; a process unit configured to be attached to and removed from the main body, the process unit being configured to integrally hold a plurality of image carriers arranged in a first direction; a plurality of developing cartridges provided in corresponding association with the image carriers, the developing cartridges configured to be attached to and removed from the process unit, each of the developing cartridges including a corresponding developer carrier, each of the developing cartridges being configured to supply developer to a corresponding image carrier; and a pressing mechanism provided in the main body, the pressing mechanism configured to press the developing cartridges, when attached to the process unit, in a direction that the developer carriers contact the image carriers.