PURPOSE: To prevent a toner image from being formed on the stereoscopic image surface of the surface of a sheet by forming the image whose surface and rear surface are inverted on the rear surface of a heat expansionary sheet with toner whose light absorption is excellent, and casting the light on the heat expansionary sheet.

CONSTITUTION: The image of an original is copied on a base material 1 on a side opposite to the covered layer 2 of the heat expansionary sheet P. By inverting the surface and the rear surface of the image of the original at such a time, the stereoscopic image finally becomes a normal image. And a toner image 5 is formed with the toner whose light absorption is excellent (for example, black toner). Next, the light is cast on the heat expansionary sheet P. Then, the black toner of the image 5 absorbes the energy of light and generates heat, so that fine globes 3 in the covered layer 2 are expanded to protrude the covered layer 2 and the stereoscopic image can be formed. Since the toner image is formed on the rear surface of the sheet and it is not formed on the stereoscopic image surface, the toner is not separated from the stereoscopic image surface and coloring can be freely executed after forming the stereoscopic image.