The coating method includes the intercoating step for spraying the intercoating paint over a substrate after undercoating, the intercoat drying step for drying the intercoat on the substrate, the overcoating step for spraying the overcoating paint over the dried intercoat on the substrate, and the overcoat drying step for drying the overcoat. In the intercoating step, the intercoating paint is sprayed in such an amount as causing sag, that is, in an amount beyond its sagging threshold value. In the intercoat drying step, the substrate is rotated about its horizontal and longitudinal axis to dry the intercoat.