An image forming apparatus capable of forming both of erasable images and images to be stored, and increasing the number of times that a single sheet with an image can be repetitively decolorized and reused. The apparatus includes a photoconductive element for electrostatically forming a latent image representative of image data. A developing device develops the latent image formed on the photoconductive element by either of an ordinary undecolorizable toner and a decolorizable toner.