Abstract: The object of this invention is to provide a highly reliable penetrating type X-ray tube and a manufacturing method thereof, preventing interfacial exfoliation between a transmission window and a target film before it happens. This invention is characterized in that at least one intermediate film 39 of at least one metal element or an alloy thereof selected from a group of copper, chromium, iron, nickel, etc. between x-ray penetrating window plate 37 of beryllium stuck vacuum-tightly to a portion of evacuated envelope 33, and target film 40 of tungsten which is provided on the evacuated side of the window plate and emanates X rays is formed by a physical method such as spattering.