Provided is an ultraviolet sterilizer which uses as a light source a deep ultraviolet light-emitting diode which has low power consumption and long life compared to mercury lamps, wherein this compact and easily maintainable sterilizer is capable of irradiating a body to be sterilized with high-intensity deep ultraviolet light for efficient sterilization. This ultraviolet sterilizer sterilizes by irradiating deep ultraviolet light onto the body to be sterilized which flows through a flow path (140) having the periphery composed of a UV-transparent material, wherein units (130) are formed and arranged on the periphery of the light path, said units comprising a light source, which comprises multiple ultraviolet light-emitting elements arranged and formed into a module (110), and a condenser (120), which condenses deep ultraviolet light emitted from the ultraviolet light-emitting elements in the module, and the body to be sterilized is irradiated with deep ultraviolet light condensed by the condensers.
