An image forming apparatus includes: a first image forming unit which forms a first image on a first recording medium with a first material that is not thermally decolorizable; a second image forming unit which forms a second image on a second recording medium with a second material that is thermally decolorizable; a fixing device which is on a common carrying path shared by the first recording medium and the second recording medium and fixes the first image to the first recording medium; and a controller which controls the fixing device so that a temperature of the fixing device is lower than a decolorizing temperature of the second material when the second recording medium reaches the fixing device.