PROBLEM TO BE SOLVED: To provide an ultraviolet irradiation device capable of efficiently irradiating and sterilizing an object to be sterilized with ultraviolet light with a simple structure. SOLUTION: An ultraviolet light irradiation device 1 is provided on a cylindrical housing 2, a light source 4 for emitting ultraviolet light, and an inner wall of the housing 2, and guides the ultraviolet light emitted from the light source 4. And a light guide 6. The light guide 6 has a tubular circling portion and an incident portion that irradiates ultraviolet light to the circling portion, and guides the ultraviolet light and emits the ultraviolet light toward the inside of the space surrounded by the circling portion. .. [Selection diagram] Figure 1【課題】簡易な構成で、効率的に殺菌対象に紫外光を照射し、殺菌することができる紫外線照射装置を提供する。【解決手段】紫外光照射装置１は、筒形状の筐体２と、紫外光を出射する光源４と、筐体２の内壁に設けられて、光源４から出射された紫外光を導光する導光体６とを備えている。導光体６は、筒形状の周回部と周回部に紫外光を入射させる入射部とを有し、紫外光を導光しつつ、周回部が囲む空間の内部に向けて紫外光を放出する。【選択図】図１
