SURFACE-TREATED STEEL SHEET PROVIDED WITH ANTIRUST COATING FILM AND METHOD FOR PRODUCING SAME

A surface-treated steel sheet having a Co layer, wherein oxidation of the surface is prevented without deteriorating characteristics such as electrical conductivity. A surface-treated steel sheet which is provided with a Co layer on the surface is immersed in an antirust agent, which contains a fatty acid amine and uses water as a solvent, and then dried, thereby forming an antirust coating film on the surface of the surface-treated steel sheet. The antirust coating film containing the fatty acid amine has a thickness of 10-500 AA (in terms of SiO2) as determined by XPS depth analysis. Preferably, the fatty acid amine is benzenemethanamine or trimethylamine, and more preferably, the fatty acid amine additionally contains benzotriazole.