To provide a coating film excellent in performances such as water resistance, weather resistance, adhesion, etc., as a coated film on a metallic material to be coated such as iron, an aluminum steel plate, etc.

This method for applying the coating material composition for the coated steel plate is characterized by comprising processes (1) to (4). Process (1): A process for applying the following thermosetting coating material composition (A) for forming a coating film. The thermosetting coating material composition (A) comprises a composition containing a base resin containing an epoxy resin, acrylic resin and amino resin, and a blocked polyisocyanate compound. Process (2): A process for setting the coated material having the thermosetting coating material (A) or evaporating a solvent by a preliminary heating. Process (3): A process for further applying a thermosetting coating material composition (B) on the coated material obtained by the above process for forming the coating film. The thermosetting coating material composition (B) comprises a composition containing a base resin containing an epoxy resin, acrylic resin and amino resin and a blocked polyisocyanate compound. Process (4): A baking process for heating and hardening the obtained coated material having the thermosetting coating material compositions (A) and (B) at the same time.