X-ray tube

An objective of this invention is to provide an X-ray tube, which can stably irradiate X-ray in an irradiation area extending in a predetermined direction under the desired conditions. The X-ray tube comprises: a substrate 4 made of a 426 alloy in which an opening part 6 is formed; an X-ray transmissive window 5 of titanium foil disposed by way of plugging the opening part 6 of the substrate 4; a container part 3 of flat box shape installed on the substrate 4 with an internal vacuum state; an X-ray target 7 provided in the opening part 6 of the interior of the container part 3; and an electron source provided in the interior of the container part 3 for the electron incident on the X-ray target 7. Further, the electron source has a line-shaped cathode 9, a first control electrode (10) to draw out electrons from the cathode 9, and a second control electrode (11) to limit the irradiation range of the drawn out electrons. At this time, the X-ray which is emitted from the X-ray transmissive window 5 extends radial