PURPOSE: To emit multiple color shines from a design having an oxide film with which a substrate is covered by irradiating it with light and heat of laser.

CONSTITUTION: A laser beam is applied from the side of an oxide film B with which a metallic surface of a substrate 1 made of a material such as resin with metal-plated, stainless steel, aluminum or the like is covered, toward the substrate 1 which is therefore subjected to a thermal change to cause a thermal change in the oxide film B. When light is applied to the thermally changed part B' of the oxide film B, multi-color light is reflected therefrom, that is, it is possible to provide a design which can emit multi-color light.