A method is provided including a step of preparing a base member; a step of preparing a metal mold which comprises a reference surface and plural projection-shaping die parts which have ring-like protruding sections projecting from a reference surface and surrounding hollow spaces which are shaped to match with the profiles of the projections; a step of placing a thermoplastic or thermosetting sheet-like molding material on the base member; a step of pressing the metal mold against the molding material placed on the base member, pressurizing the molding material at least with the ring-like protruding sections and accordingly bonding the molding material thus pressurized with the ring-like protruding sections to the base member, and forming and shaping projections from the molding material which is opposed against the insides of the hollow spaces surrounded by the ring-like protruding sections; and a step of leaving on the base member the molding material which is opposed against the plural projection-shaping die parts and stripping off the molding material other than the molding material which is opposed against the plural projection-shaping die parts.