X-ray tube and X-ray source

In an X-ray source and an X-ray tube , there is formed a shield portion adapted to shield the portion W where a target support body and an opening portion on the other end side of a valve are fixed to each other when viewed from the one end side of the valve . Therefore, the generation of discharge between the one end side of the valve and the fixation portion W can be suppressed. Also, the other end portion of the valve is formed as a narrowed portion and the opening portion on the other end side of the valve is fixed to the target support body , whereby the shapes of the valve and the shield portion can be made simpler than in conventional X-ray tubes in which an inner cylindrical portion is formed in a valve. Such a simple structure can improve the stability of an electric field in the valve when generating X-rays and thereby achieve an effective suppression of the generation of discharge in the valve