Abstract: A process for producing a metal plating film, comprising providing a base element with convex curved surface, depositing a metal plating film on the base element surface and detaching the metal plating film from the base element. The base element surface on which the metal plating film is deposited is convex curved, so that the metal plating film of convex sectional configuration is formed on the base element surface. Internal stress (tensile stress) occurs within the thus formed metal plating film, so that when the metal plating film is detached from the base element and transferred on a dielectric sheet, the metal plating film is transfigured toward planarization. Therefore, on transfer recipient materials, such as the dielectric sheet, having a metal plating film transferred thereonto, deformation and damaging of such a metal plating film can be effectively prevented to thereby contribute to an improvement of production efficiency.