An ultraviolet irradiation device having higher processability and interfacial adhesiveness, and allowing downsizing is provided. The ultraviolet irradiation device includes an enclosure configured to include a hollow portion being formed inside and being capable of introducing an irradiation object, an outer periphery of the enclosure being covered by a covering portion, and a light source configured to be arranged in an area not covered by the covering portion of the enclosure and project light toward the hollow portion. The covering portion is formed of thermoplastic resin fiber. Processability and interfacial adhesiveness can be improved by forming the covering portion with thermoplastic resin fiber. Consequently, a structure advantageous for downsizing of the ultraviolet irradiation device is provided.
