Abstract: A method for the formation of a paint film in which an aluminum or aluminum alloy part is subjected to an anodic oxidation treatment and an anodic oxide film is formed on the surface of the aluminum or aluminum alloy part, an anti-rust primer is coated on said anodic oxide film and an anti-rust primer paint film is formed and, as required, a top-coat paint is coated on said anti-rust primer paint film and a top-coat paint film is formed in which said anti-rust primer includes a base resin comprising hydroxyl group containing epoxy resin and a hardening agent, selected from among melamine resin and polyisocyanate, and barium sulfate, and the proportion of said barium sulfate included is a proportion within the range from 20 to 70 parts by mass per 100 parts by mass in total of the solid fractions of the base resin and the hardening agent.