PURPOSE: To provide a car coating compsn. enhancing self-adhesiveness and reflectivity by forming a leafing aluminum flakes-containing undercoat layer on a metallic base material and subsequently forming a transparent topcoat layer thereon.

CONSTITUTION: An undercoat compsn. (A) is obtained by compounding a first film forming material (a) selected from an acrylic resin (i), an alkyd resin (ii), a polyurethane resin (iii), a polyester resin (iv) and an aminoplast resin (v), leafing aluminum flakes (b) and a volatile org. solvent (c) for the component (a). Separately, a topcoat compsn. (B) is obtained by compounding a second film forming material (d) selected from the components (i)-(v), an acidic self- adhesiveness accelerator (e) selected from phosphoric acid, an alkylbenzenesulfonic acid having a 1-12C alkyl group and a volatile org. solvent (f) for the component (d). The component A is applied to a metallic base material to be cured to form an undercoat layer and the component B is subsequently applied to be cured to form a transparent topcoat layer.