PROBLEM TO BE SOLVED: To obtain a light irradiation device including a plurality of irradiation surfaces in a light emission part, and to provide a light irradiation therapy/prophylaxis device.SOLUTION: The light irradiation device 1 comprises a light emission unit 2 which emits light, a reflection unit 3 which reflects irradiation light from the light emission unit 2 and a light guide unit 4 which guides the reflected light from the reflection unit 3 to a subject to be irradiated. The light guide unit 4 comprises a first and second light guide face 12 and 18. The reflection unit 3 comprises a first reflection unit 16 which reflects a portion of radiation light to the first light guide face 12, a second reflection unit 19 which reflects incident light to the second light guide face 18, and a third reflection unit 20 which reflects a portion of the other radiation light to the second reflection unit 19 as the incident light. The third reflection unit 20 is arranged so as to incline to the light emission unit 2 and has a translucent units 27 wherein the closer the translucent unit is to the light emission unit 2, the greater the quantity of translucent of the radiation light.COPYRIGHT: (C)2013,JPO&INPIT【課題】本発明は一つの発光部で複数の照射面を有する構成とすることができる光照射装置及び光照射治療・予防装置を得る。【解決手段】本発明の光照射装置1は、光を放射する発光部2と、該発光部2からの放射光を反射する反射部3と、該反射部3からの反射光を被写体に導光する導光部4とを備え、導光部4は、第1及び第2の導光面12,18を有し、反射部3は、第1の導光面12に放射光の一部を反射する第1の反射部16と、第2の導光面18に入射光を反射する第2の反射部19と、該第2の反射部19に放射光の他の一部を前記入射光として反射する第3の反射部20とを有し、該第3の反射部20は、発光部2に対して傾斜するよう配置され、且つ、発光部2に近づくほど放射光の透過量が増加する透過部27,…を有する構成である。【選択図】図4
