After at least one toner image is transferred to a medium to which an image is transferred from at least one of a plurality of image forming stations used, at least one toner image is transferred from at least one of the rest of the image forming stations, and this transfer operation is repeated a plurality of times to transfer toner images to the medium to which an image is transferred. In this manner, the toner images on the medium to which an image is transferred are formed using a desired number of color toner including a transparent toner. In addition, the order in which the transparent toner is transferred from the image forming station that is used for the transparent toner and toner other than the transparent toner is transferred from image forming stations in which the transparent toner is not used can be freely or automatically selected.