An image forming apparatus includes a conveying unit that conveys a recording medium in a predetermined direction, a thermal transfer sheet traveling unit that causes a thermal transfer sheet to travel in a predetermined direction, a modification sheet moving unit that moves a surface modification sheet, a thermal head that applies thermal energy and thermally transfers sequentially a dye layer and a protective layer of the thermal transfer sheet onto the recording medium while the dye layer or the protective layer opposes the surface of the recording medium, and a modification sheet protecting unit disposed in a movement path of the surface modification sheet, and configured to prevent adhesion of dust to the surface modification sheet or to eliminate the adhesion. After forming the image onto the recording medium using the thermal transfer sheet and forming the protective layer that protects the image, the surface modification portion of the surface modification sheet is aligned with a plane in which the protective layer is formed, so that heat and pressure are applied by the thermal head to modify the surface state of the protective layer formed at the recording medium.