Apartments covered with a metal roof made from galvalume steel are prevailing due to their economic and technical advantages. The metal roof, however, has disadvantages in terms of the installation of air-termination system on it because of the slip thickness of the metal roof. In this paper, the impacts of the lightning current to a metal roof were verified experimentally with a short lightning impulse current (10/350[${mu}s$]). Also, we developed various supporters of air-termination conductor for the metal roof and verified their excellent workability and economical strength through field application test.