According to one embodiment, a developing device in which a decolorizable developing agent containing encapsulated colorant microparticles each including a core containing a color developable compound, a color developer, and a decolorizing agent is accommodated and a developing device in which a transparent developing agent containing a binder resin is accommodated are provided, respectively, and an image is formed by transferring a transparent developing agent image onto a region capable of covering a decolorizable developing agent image, followed by fusing the image. Further, in the second image formation and thereafter, the using amount of the transparent developing agent is decreased as compared with that in the first image formation.