This invention relates to a method for forming a multi-layer coating film which is characterized by applying a base coating (A) which contains a phosphoric acid group-containing resin composition, and, without curing the same, applying a leafing type aluminum flake pigment-containing metallic composition (B), and, after curing both of said base coating (A) and said metallic composition (B), applying, on the coated surface of said metallic composition (B), a composition (C) which contains a phosphoric acid group-containing non-aqueous dispersion which comprises polymer particles dispersed in a solution of macromolecular dispersion stabilizer dissolved in an organic solvent, said polymer particle being a particle of polymer which is composed of a phosphoric acid group-containing polymerizable unsaturated monomeric unit as a constituent component, and applying a clear coating (D). With use of said method, there can be improved interlayer adhesivity between a metallic coating film, which is formed from a leafing type aluminum flake pigment, and another coating film adjacent thereto, without reducing the excellent effects such as dense metallic feeling of the coated surface, a chrome plating-like finish, and strong brightness feeling and strong flip-flop properties, which are produced by such a metallic coating film.