An image forming apparatus includes a housing defining a sheet convey path through which a sheet is conveyed, a transfer belt disposed in the sheet convey path within the housing, a plurality of photosensitive members disposed opposite to the transfer surface from below in the housing, and a plurality of developing units disposed in the housing such that each of the developing units corresponds to one of the photosensitive members. The housing includes a first body configured to accommodate the developing units detachably and a second body disposed above the first body and configured to accommodate the transfer belt and the photosensitive members. The second body is configured to pivot around a pivot axis located on a first end of the first body and separate upward from the first body such that the developing units are exposed from the first body.