Irradiation light LA and irradiation light LB, which are to be projected toward an irradiation target object from a plurality of irradiation light projection units, respectively, are corrected so as to be ached with outlines of the irradiation target object, which are viewed individually from the irradiation light projection units. In such a way, a surface of the irradiation target object is coated with irradiation light LA′ and irradiation light LB′, which are narrower in range than the irradiation light LA and the irradiation light LA. In such a way, the irradiation target object having an arbitrary shape is coated with the plural pieces of irradiation light with high accuracy.