Abstract: A method of forming a three-dimensional colored design, such as a simulated animal bone, in production material which is to be formed into an article such as a handbag, including forming a master, forming a mold member, and applying a colored design to the production material. A light-transmitting film, which includes a colored design formed on one surface thereof, is positioned intermediate the production material and the mold member with the colored design facing the production material. The production material, the light-transmitting film, and the mold member are heated and pressed together in a high frequency heating press, and the production material and light-transmitting film are hardened, so as to form the three-dimensional colored design in an efficient, convenient and economical manner.