An image forming apparatus includes an apparatus main body, a plurality of photoreceptor drums, a plurality of developing devices, a frame, an intermediate transfer unit, a secondary transfer roller, first positioning portions, and second positioning portions. The secondary transfer roller forms a secondary transfer nip portion with the first roller where the toner images are transferred to a sheet. The first positioning portions are arranged at the intermediate transfer unit and the frame. The first positioning portions position the intermediate transfer unit in a second direction inside the apparatus main body. The second positioning portions are arranged at the intermediate transfer unit and the apparatus main body. The second positioning portions position a distal end side in the mounting direction of the intermediate transfer unit in a third direction inside the apparatus main body. The third direction intersects with the first direction and the second direction.