PROBLEM TO BE SOLVED: To provide a UV bactericidal device for fluid which enables a larger amount of UV-LED light energy to be used for sterilization, as compared with the prior art.SOLUTION: A UV bactericidal device for fluid has: first piping inside which fluid flows at least one UV-LED light source provided in the first piping to irradiate the inside of the first piping and a reflection face provided on the inner face of the first piping. The reflection face has a reflection part for reflecting the UV-LED light from the UV-LED light source, toward the central side of the first piping in lengthwise direction.
