PROBLEM TO BE SOLVED: To provide an ultraviolet sterilization device achieving suitable bactericidal activity, by adjusting the light intensity of emitted ultraviolet light.SOLUTION: The ultraviolet sterilization device for sterilizing a predetermined target site with ultraviolet light emitted by an emission part 10 includes control means 30 which controls the light intensity by measuring the integrated time of ultraviolet emission by the emission part 10, and increasing the light intensity of ultraviolet light emitted by the emission part 10 by a predetermined amount in the case that the measured integrated time exceeds a predetermined reference time.
