An ultraviolet irradiation apparatus includes: a first substrate; a second substrate; electrodes disposed directly or indirectly on the first substrate; a dielectric layer covering the electrodes; a sealant joining together the first and second substrates; a light-emitting layer that is disposed directly or indirectly on the dielectric layer and/or a surface of the second substrate; and a reaction vessel disposed directly or indirectly on a surface of the second substrate. The reaction vessel includes a tubular structure, an inlet channel and an outlet channel. The tubular structure has a ratio ha/hc of 5 to 10, where ha is a diameter of a circle inscribed in an inner bottom surface of the tubular structure, and hc is an inner height of the tubular structure.