PURPOSE: To finish an inner glossy surface of shell in a metallic tone by forming patterns such as figures and letters utilizing the combination of a metal film coated part and the exposed part of the inner glossy surface and by laying a topcoating on the pattern containing section.

CONSTITUTION: Using a pearl oyster shell, a half-finished product 1 is manufactured, which is button for clothes with the inner glossy surface of the shell remaining exposed. An undercoating 2 of transparent resin is placed on the inner glossy surface, and the half-finished product 1 is then set in a vacuum evaporator for the deposition of an aluminum coating 3 and gold coating 4. On the gold coating 4, figures or letters are printed using a resist ink 5, the un-inked part 6 is removed from the gold coating 4, and then the resist ink 5 is removed. Finally a topcoating 7 of transparent resin is laid for the production of a product 8. Thereby, the shell inner glossy surface can be finished in a metallic tone.