To provide a coating method where a wet-on-wet coating system consisting of undercoating and intermediate coating can be realized while preventing the defect in a skin.

In the coating method where at least three coating materials including an undercoating material, an intermediate coating material and a finish coating material are applied, the intermediate coating material in which the minimum viscosity ηmin and a viscosity reduction time td in a time t vs. viscosity η curve on coating material baking satisfy a specified relation is used. The undercoating material is applied, then the intermediate coating material is applied in a wet-on-wet manner, and they are simultaneously baked and hardened. Finally, the finish coating material is applied.