An image forming apparatus can easily attach or detach a plurality of attachable and detachable units to or from the apparatus main body as a single unit or individually. An intermediate transfer apparatus is supported on a left guide rail and a right guide rail, and is attachable to and detachable from the image forming apparatus main body. A cleaning apparatus that cleans the intermediate transfer belt of the intermediate transfer apparatus is supported by an upper rail and a lower rail so as to be attachable to and detachable from the intermediate transfer apparatus. The detachment direction of the intermediate transfer apparatus and the direction of detachment of the cleaning apparatus are configured to be the same.