An image forming apparatus including a main body housing including a first side wall, a second side wall, a rear wall, and a front wall having an opening. The apparatus also includes a process unit supporting a photosensitive drum, an exposure device, a transfer roller, and a fixing device spaced upward from the photosensitive drum. The process unit is movable between an inner position where the process unit is accommodated inside the main body housing and an outer position where at least a part of the process unit is drawn out of the main body housing through the opening. When the process unit is at the inner position, the transfer roller is at a position between the rear wall and the photosensitive drum. The process unit is configured to move downward as the process unit moves from the inner position to the outer position.