A first mode to form a toner image of single color where a pressure contact release section T changes a primary transfer section 7 to be in a pressure contact state, and a second mode to form an overlapped toner image where the pressure contact device T changes a plurality of the primary transfer sections 7 to be in the pressure contact state can be executed, wherein a speed difference D1 between an image carrier 1 and an intermediate transfer belt 6 in the first mode is controlled to be greater than a speed difference D2 between the image carrier 1 and the intermediate transfer belt 6 in the second mode.