To improve the yield of manufacturing liquid crystal panels with high performance by uniform irradiation with UV rays.

A pair of electrodes 13a, 13b for discharge is disposed opposing to each other in an axial direction of a light emitting tube 12 made of quartz glass having UV transmitting property and having an air-tight discharge space 11. An enclosure composed of a rare gas, mercury, halogen and light-emitting metal, in an enough amount to maintain an arc discharge state is sealed in the discharge space 11 to constitute a UV ray lamp 100, so as to allow the lamp to emit UV rays upon lighting. An irradiation object is irradiated with UV rays while cooling the UV ray lamp 100 by a cooling unit 200 and disposing a reflector 19 in the opposite side to the irradiation object. By diffusing UV rays incident to a plurality of reflecting surfaces 61 in different directions of the reflector 19, the illuminance of the UV rays irradiating the object is made uniform.