A fluid sterilization apparatus includes: a flow passage for causing a fluid to flow； and a light source that irradiates the fluid flowing in the flow passage with ultraviolet light of a wavelength of 290∼310 nm. The fluid may contain an aromatic compound. The flow passage may include a straight tube extending in a longitudinal direction, the fluid may flow in the flow passage in a laminal flow state, and the light source may emit ultraviolet light in an intensity distribution in which an ultraviolet light intensity near a center in a cross section of the flow passage perpendicular to a longitudinal direction is higher than an ultraviolet light intensity around.
