A light irradiation device (151) includes a UV lamp (153), first and second optical filters (164, 165) which transmit and block wavelengths within different specific ranges, and a filter switching mechanism (162) which selectively interposes the first and second optical filters (164, 165) between the UV lamp (153) and an optical lens. The blocking wavelength of the first optical filter (164) is relatively longer than that of the second optical filter (165). The first optical filter (164) is interposed between the UV lamp (153) and the optical lens since the start of curing a coating solution until a lapse of a predetermined period of time. When the predetermined period of time has elapsed, the second optical filter (165) is interposed between the UV lamp (153) and the optical lens to replace the first optical filter (164).