An intermediate transfer drum has at least a drum main body having a volume resistivity of 10.sup.4 to 10.sup.8 .OMEGA.cm, and an insulating layer provided on an outer surface of the drum main body. A first transfer voltage applying roller is provided inside the intermediate transfer drum so as to be opposite to a photosensitive drum and so as to be in contact with an inner surface of the intermediate transfer drum. A transfer roller is provided inside the intermediate transfer drum so as to be opposite to a second transfer grounded roller and so as to be in contact with the inner surface of the intermediate transfer drum. By thus arranging an image forming apparatus wherein image formation is carried out with respect to recording paper through the intermediate transfer drum, an optimal first transfer voltage can be applied from the photosensitive drum to the intermediate transfer drum, while an optimal second transfer voltage can be applied from the intermediate transfer drum to the recording medium. As a result, the first transfer and the second transfer are individually and simultaneously carried out. Furthermore, since the intermediate transfer drum does not become large in size, it is avoidable that the image forming apparatus becomes bulkier, while the lowering of the copying speed can also be suppressed.