Abstract: Ultraviolet irradiating apparatus including a generally enclosed upright cylindrical housing defining an entry opening and an exit opening, a linear ultraviolet radiation source vertically mounted generally along the central axis of the housing, multiple sections of reflectors formed with zig-zag configurations disposed around the cylindrical interior wall of the housing to a height about the same as the radiation source with the corners of the angles between the zig-zag reflectors disposed generally transversely to the length of the radiation source. The reflectors present specular surfaces to the radiation source which reflect about 80% of the original ultraviolet rays from the radiation source. The reflectors preferably may be formed from specular aluminum sheet. A parts conveyor is mounted to convey parts into the entry opening, then through a generally circular horizontal path between the radiation source and the reflectors and out through the exit opening.