PROBLEM TO BE SOLVED: To provide a decorative coating film (radio wave transmission cover) which exhibits red color at the initial color and a high discoloration suppression effect.SOLUTION: A decorative coating film is formed by dispersing fine particles of silver-copper alloy into a resin component. Therein, a content of copper in the silver-copper alloy is 0.3 mass% or more with respect to silver, preferably is 0.5 to 20.0 mass% and particularly preferably is 0.8 to 6.5 mass%, a crystallite diameter of the fine particle of the silver-copper alloy is set to be 2 to 98 nm and, thereby, a high discoloration suppression effect is provided. The decorative coating film is used for covering the skin of a resin base formed for a front grille such as emblem of a vehicle and has a radio wave transmission property (electrical insulation).
