An ultraviolet irradiation device comprising: a lamp house on at least one surface of which a light extraction surface is formed; an excimer lamp accommodated in the lamp house in a position separated from the light extraction surface in a first direction (X), the excimer lamp that emits ultraviolet light (L1), a main emission wavelength of which belongs to a first wavelength band of 190-225 nm; a first electrode arranged in contact with an outer surface of an luminous tube of the excimer lamp ; a second electrode arranged in contact with the outer surface of the luminous tube of the excimer lamp in a position separated from the first electrode in a second direction (Y) parallel to a tube axis of the excimer lamp ; an optical filter that is arranged on the light extraction surface and substantially transmits the ultraviolet light (L1) in the first wavelength band and does not substantially transmit ultraviolet light (L1) of a wavelength of 240-300 nm; and a reflecting surface that is a surface located outside the luminous tube of the excimer lamp and inclined with respect to the light extraction surface as seen in the second direction (Y), the reflecting surface exhibiting reflectivity with respect to the ultraviolet light (L1) in the first wavelength band, wherein the first electrode is a first electrode block in the shape of a block, the second electrode is a second electrode block in the shape of a block, and at least one of the first electrode and the second electrode includes a tapered surface forming the reflecting surface in a position away from the excimer lamp in a third direction (Z) orthogonal to the first direction (X) and the second direction (Y). a lamp house on at least one surface of which a light extraction surface is formed; an excimer lamp accommodated in the lamp house in a position separated from the light extraction surface in a first direction (X), the excimer lamp that emits ultraviolet light (L1), a main emission wavelength of which belongs to a first wavelength band of 190-225 nm; a first electrode arranged in contact with an outer surface of an luminous tube of the excimer lamp ; a second electrode arranged in contact with the outer surface of the luminous tube of the excimer lamp in a position separated from the first electrode in a second direction (Y) parallel to a tube axis of the excimer lamp ; an optical filter that is arranged on the light extraction surface and substantially transmits the ultraviolet light (L1) in the first wavelength band and does not substantially transmit ultraviolet light (L1) of a wavelength of 240-300 nm; and a reflecting surface that is a surface located outside the luminous tube of the excimer lamp and inclined with respect to the light extraction surface as seen in the second direction (Y), the reflecting surface exhibiting reflectivity with respect to the ultraviolet light (L1) in the first wavelength band, wherein the first electrode is a first electrode block in the shape of a block, the second electrode is a second electrode block in the shape of a block, and at least one of the first electrode and the second electrode includes a tapered surface forming the reflecting surface in a position away from the excimer lamp in a third direction (Z) orthogonal to the first direction (X) and the second direction (Y). <EOS>