According to one embodiment, an ultraviolet water treatment apparatus includes an ultraviolet lamp unit provided with a first plumbing flange coupling on each of both ends thereof, and further provided therein with an ultraviolet irradiation tube including an ultraviolet lamp and a lamp protective tube configured to protect the ultraviolet lamp, and a cleaning device drive unit provided with a second plumbing flange coupling on each of both ends thereof and configured to drive a cleaning device configured to clean a surface of the lamp protective tube. The ultraviolet lamp unit and the cleaning device drive unit are coupled with each other on the first and second plumbing flange couplings.