Bias correction control of an intermediate transfer belt 21 on which an image of each color formed on a surface of a photoconductive body 31 is transferred, and a second transfer belt 24 in pressure contact with the intermediate transfer belt 21 to transfer a toner image onto a recording sheet by passing the recording sheet between the intermediate transfer belt 21. Contents of the bias correction control (an amount of correction control and a cycle of correction control) can be changed in accordance with states of the belts i.e. whether the intermediate transfer belt 21 and the second transfer belt 24 are in a pressure contact state or a separate state.