The X-ray tube device according to one embodiment of the invention comprises: a negative pole (36) emitting an electron in the electron trajectory direction; a positive pole target (35) provided so as to face the negative pole, and having a target surface wherewith the electron emitted from the negative pole collides to generate X-ray; a vacuum enclosing vessel (31) housing the negative pole and the positive pole target, and sealed in such a manner that the interior is vacuum-tight; and a quadrupole magnetic field generation unit (60), which forms a magnetic field by being supplied a direct current from a power source, is disposed outside of the vacuum enclosing vessel so as to be eccentric from a straight line that follows the electron trajectory, and is constituted from a quadrupole surrounding the periphery of a portion of the electron trajectory.