The coating film-forming composition includes an aromatic compound having an amino group and an aromatic ring in one molecule, and thio compound (sulfur oxoacids having a pKa of −1.9 or less and salts thereof are excluded). pH of the coating film-forming composition is 4 to 10. The thio compound is preferably one that ionized to form anions in a solution, and thiosulfate and thiocyanate are especially preferable. By bringing the coating film-forming composition into contact with the surface of a metal member, a coating film is formed on the surface of the metal member, so that a surface-treated metal member can be obtained.