A color image forming apparatus for forming a color image on a sheet by use of a plurality of photosensitive drums. The plurality of photosensitive drums correspond to a plurality of colors and have eccentric phases each shifted by a quantity corresponding to a radius of the photosensitive drum and a distance between transfer positions of the photosensitive drums. The color image forming apparatus also includes a plurality of charging units which correspond to the respective photosensitive drums, for charging the photosensitive drums. An exposure light source effects an image exposure on each photosensitive drum. A plurality of developing units correspond to the respective photosensitive drums, for forming toner images on the photosensitive drums by developing electrostatic latent images on the photosensitive drums. A plurality of transferring units, corresponding to the respective photosensitive drums, transfer the toner images on the photosensitive drums onto the sheet. The eccentric phases of the plurality of photosensitive drums are set the same on the basis of the sheet to be fed, and a color deviation of each color on the sheet can be thereby prevented.