PROBLEM TO BE SOLVED: To improve sterilization ability by heightening irradiation efficiency of ultraviolet light into fluid flowing along a channel.SOLUTION: A fluid sterilizer 10 includes a straight pipe 20 constituting a channel 12 extending in the longer direction, and a light source 40 for irradiating ultraviolet light in the longer direction toward the fluid flowing in the laminar flow state along the channel 12. The light source 40 has a light-emitting device 42 for emitting ultraviolet light, and irradiates ultraviolet light so that ultraviolet light intensity in a central vicinity has a higher intensity distribution than ultraviolet light intensity in its periphery on a cross section of the channel orthogonal to the longer direction.SELECTED DRAWING: Figure 1【課題】流路を流れる流体への紫外光の照射効率を高めて殺菌能力を向上させる。【解決手段】流体殺菌装置１０は、長手方向に延びる流路１２を構成する直管２０と、流路１２を層流状態で流れる流体に向けて長手方向に紫外光を照射する光源４０と、を備える。光源４０は、紫外光を発する発光素子４２を有し、長手方向と直交する流路の断面において中央付近の紫外光強度がその周囲の紫外光強度よりも高い強度分布となるように紫外光を照射する。【選択図】図１
