When a heat capacity of a recording medium having a base material coated with a foamable resin layer is larger than a normal heat capacity, to form a raised amount equal to that with the normal case with a normal heating quantity, a turned mirror image of the image is generated. The image is transferred onto the front face of the recording medium and fixed. The recording medium is reversed, and conveyed again to the transfer part. The turned mirror image is transferred onto the rear face of the recording medium and fixed. The recording medium is heated with the heat quantity equal to that in the normal case, and combination of heat absorbed by the turned minor image and heat absorbed by the image is transmitted to the foamable resin layer to expand the foamable resin layer.