A penetrating X-ray tube includes an electrode lead (4) holding a cathode filament (7) and a stem unit (1) to which a seal member (5), a discharge tube (2), and the like are attached by brazing, and an irradiation window frame (8) having an X-ray irradiation window (9) attached by brazing. The other side (52) of the seal member (5) is attached to an open end (83) of the irradiation window frame (8) by welding. Thus, it is possible to obtain a high-quality penetrating X-ray tube having a long service life at a low cost.