Provided is an ultraviolet irradiation device including an excimer lamp, a main emission wavelength of which belongs to a wavelength band of 190-230 nm (first wavelength band), the ultraviolet irradiation device that shows high startability. This ultraviolet irradiation device includes: a lamp house on at least one surface of which a light extraction surface is formed; an excimer lamp accommodated in the lamp house, the excimer lamp that emits ultraviolet light, a main emission wavelength of which belongs to a first wavelength band of 190-230 nm; and a start assist light source arranged in a position in which ultraviolet light, a main emission wavelength of which belongs to a second wavelength band of 250-300 nm, is capable of being irradiated to the excimer lamp.