An intermediate transfer unit of an image forming apparatus is provided between a plurality of developer containers for containing developer and a plurality of developing devices. The intermediate transfer unit includes an intermediate transfer unit for secondarily transferring primarily transferred developed images from the plurality of image carriers onto a paper, an intermediate transfer unit driving mechanism for driving the intermediate transfer unit, and a housing for supporting the intermediate transfer unit driving mechanism. One end of the housing includes a plurality of developer inlet ports positionally corresponding to the developer supply ports of the developer containers respectively, a plurality of developer outlet ports positionally corresponding to the developer receiving ports of the developing devices respectively, and a plurality of developer supply paths connecting between the developer inlet ports and the developer outlet ports respectively.