The invention which is used to apply the that the resin powder melted by the heat generated by combustion of the fuel gas by the air that is directed to a resin powder coating gun comprising a mixture air-fuel, supplied to the interior to the surface of the coating object a resin powder coated with a spray gun, and the air flow path in which the air is supplied, is the fuel gas to the air flow path and the fuel gas flow channel is connected to the fuel gas flow to be supplied, an end of the air passage and the fuel gas flow channel mix mixing flow path and the body passage that supplies the resin powder resin powder is formed and that is; The resin is provided in the end of the body of molten so that the resin powder to be supplied from the resin powder passage molten by the heat generated as the combustion air and fuel gas supplied from the mixing flow path applying the resin powder, the molten coating object powder the cap member is received in and temporarily; The fuel gas supplied through the air and the fuel gas flow channel is supplied via the air flow path to be quickly mixed air fuel mixture portion is provided at one side of the body; By having the air and the mixing of the fuel gas so as uniformly achieved by the fuel is sufficiently melted to transfer more heat to the resin powder by ensuring complete combustion, as well as the adhesion to the coating object to be good fuel it is completely burned soot the colors are so vivid that it does not cause effects that can be applied to the cleaner.