To make equipment compact, to simplify a sterilization process, and to enhance sterilization efficiency.SOLUTION: A vessel sterilizer includes an insertion 10 that can be inserted in a vessel P, a fluid supply unit for sending a sterilization fluid G into the vessel P, an ultraviolet light source 14 installed in the insertion 10 for emitting ultraviolet rays for sterilization, and a shield cover 34 for covering the ultraviolet light source 14 to shield the ultraviolet light source 14 from the sterilization fluid G. Sending the sterilization fluid G and emitting the ultraviolet rays for sterilization are conducted alternately or simultaneously.SELECTED DRAWING: Figure 2【課題】装置をコンパクト化できるとともに、殺菌行程の単純化と殺菌効率の向上を行う。【解決手段】容器Ｐ内に挿入可能な挿入体１０と、殺菌用流体Ｇを容器Ｐ内に流送する流体供給部と、挿入体１０に設置されて殺菌用の紫外線を照射する紫外線光源１４と、紫外線光源１４を覆い殺菌用流体Ｇから紫外線光源１４を遮蔽する遮蔽カバー３４と、を備え、殺菌用流体Ｇの流送と殺菌用の紫外線を照射とを順次または同時に行う。【選択図】図２
