Provided is an X-ray tube capable of obtaining a clear X-ray image by reducing unnecessary X-rays radiated from a holder shaft. The X-ray tube includes an electron source 12 for generating an electron beam B, an anode 13 for accelerating the electron beam B and having a hole 13a allowing the electron beam B to pass through, a cylindrical holder shaft 14 forming a passage for allowing the electron beam B to pass through a hole 13a of the anode 13, a magnetic lens 17 arranged around the holder shaft 14 and configured to converge the electron beam B, a target holder 15 connected to the holder shaft 14, a target 16 arranged in the target holder 15 so that the electron beam B collides with the target 16, and an irradiation window 15b arranged in the target holder 15 and configured to extract X-rays generated from the target 15 to the outside. The inner wall of the holder shaft 14 is made of a carbon material to reduce X-rays generated when the electron beam B hits the holder shaft 14.