Blue color forming sub-layer (205), green color forming sub-layer (206) and red color forming sub-layer (207) which start to form colors upon application of different amounts of energy are superposed on the image surface of optical disc (D). The color forming sub-layer which requires the smallest amount of energy to form color is first illuminated with laser of the power required to realize color formation from that sub-layer; subsequently, this sub-layer is illuminated with ultraviolet radiation to fix the color it has formed. Then, the next color forming sub-layer is illuminated with laser of the required power and after fixing the color it has formed, the last color forming sub-layer is illuminated with the required laser to form color.