To be able to achieve further small-sized formation and light-weighted formation and to promote a sensitivity by further efficiently detecting a fluorescent X-ray or the like in an X-ray tube and an X-ray analyzing apparatus, there are provided a vacuum cabinet 2 inside of which is brought into a vacuum state and which includes a window portion 1 formed by an X-ray transmitting film through which an X-ray can be transmitted, an electron beam source 3 installed at inside of the vacuum cabinet 2 for emitting an electron beam e, a target T generating a primary X-ray X1 by being irradiated with the electron beam e and installed at inside of the vacuum cabinet 2 to be able to emit the primary X-ray X1 to an outside sample S by way of the window portion 1, and an X-ray detecting element 4 arranged at inside of the vacuum cabinet 2 to be able to detect a fluorescent X-ray and a scattered X-ray X2 emitted from the sample S and incident from the window portion 1 for outputting a signal including energy information of the fluorescent X-ray and the scattered X-ray X2.