Provided is a sterilization device designed to be more compact while being designed to improve sterilization efficiency. A sterilization device (100) equipped with a housing (110) that has a flow channel (R) for the fluid being sterilized and an LED element (122) that is provided in the housing (110) and irradiates ultraviolet rays into the flow channel (R) is characterized in that: the inner wall surface of the flow channel (R) has a pair of reflecting surfaces (first reflecting surface (111) second reflecting surface (112)) that cause ultraviolet rays irradiated from the LED element (122) to be reflected multiple times while directing same from one end of the flow channel (R) to the other and the first reflecting surface (111) side is provided with a return surface (111a) which is configured from a surface that is perpendicular to the optical axis of the light after being reflected multiple times from one end to the other and which returns said light toward the original direction.
