An image forming apparatus including: colored toner image forming devices each developing an electrostatic image with colored toner to form a colored toner image; a transparent toner image forming device developing an electrostatic image with transparent toner to form a transparent toner image; a transfer device superimposing and transferring the colored toner images and the transparent toner image on a transfer medium; and a fixing device fixing the superimposed toner images on the transfer medium. An image forming operation by the transparent toner image forming device is controlled in such a manner that the heights of the superimposed toner images fixed by the fixing device are substantially constant. The transparent toner has an absolute value for a charge amount per unit weight smaller than an absolute value for the charge amount of each of the colored toners per unit weight.