PROBLEM TO BE SOLVED: To sufficiently sterilize liquid with ultraviolet rays even if the liquid has low ultraviolet transmittance.SOLUTION: In a liquid sterilization method where liquid is made to pass in front of an ultraviolet irradiator 11 and irradiated with ultraviolet rays to be sterilized, while the thickness of the liquid in a part irradiated with the ultraviolet rays is restricted so that the illuminance ratio of ultraviolet illuminance on the surface of the liquid to ultraviolet illuminance at the farthest point from the surface is 20% or more, the ultraviolet rays are irradiated at an irradiation intensity or for an irradiation time capable of obtaining the ultraviolet irradiation amount, reducing the survival rate of microorganisms to be sterilized to a predetermined value or less, in the part irradiated with the ultraviolet rays.COPYRIGHT: (C)2015,JPO&INPIT【課題】紫外線透過率が悪い液体であっても充分に紫外線殺菌することができるようにする。【解決手段】液体を紫外線照射器11の前に通し、当該液体に紫外線を照射して殺菌する液体殺菌方法において、前記紫外線が照射される箇所での液体の厚みを、前記液体の表面での紫外線照度と当該表面からの最遠点での紫外線照度との比である照度比を20%以上とする厚みに制限しつつ、殺菌する微生物の生残率を所定値以下とする紫外線照射量が前記紫外線の照射箇所において得られる照射線強度、或いは照射時間で紫外線を照射する構成とした。【選択図】図1
