To provide a gold plating treatment technique for an electric contact by which stains are hard to be adhered, and, even in their adhering, the stains can easily be removed, and the low contact electric resistance and excellent wear resistance characteristic of gold can be maintained.

In the composite gold plating film, a stock whose upper face is provided with a substrate improving the adhesion with gold or a fluorine based high polymer compound is subjected to plating treatment to precipitate gold and a fluorine based high polymer compound. The plating film is subjected to heat treatment at 220 to 360°C. Water repellency of 100 to 140 degrees by the contact angle of water in the surface can be obtained. Further, low contact electric resistance of ≤1.0 Ω can be obtained.