A sterilization apparatus is provided with: a light source, which has a semiconductor light-emitting element that emits ultraviolet light； a housing, which forms a flow passage through which a fluid subject to sterilization passes； a light receiving unit, which receives a portion of the ultraviolet light emitted from the light source and detects the amount of ultraviolet light that has been received； and a control unit, which controls the output of the semiconductor light-emitting element based on information regarding the amount of ultraviolet light acquired from the light receiving unit. The housing has an incidence portion on which ultraviolet light becomes incident and a reflection portion, which reflects the ultraviolet light at the inner surface thereof. The light receiving unit is provided at a position where the light receiving unit can receive the portion of ultraviolet light that has been transmitted through the reflection portion.
