To provide an X-ray of output higher than ever before with a small focal size.SOLUTION: An X-ray CT apparatus according to an embodiment includes an X-ray tube, an X-ray detector, a first rotation part, and a second rotation part. The X-ray tube includes a cathode for irradiating a thermal electron, and an annular anode for generating an X-ray upon receipt of the thermal electron, which is provided over the periphery of an imaging center. The X-ray detector is provided at a position which is irradiated with the X-ray generated by the anode of the X-ray tube. The first rotation part holds the cathode, the anode, and the X-ray detector rotatably in a circumferential direction. The second rotation part is held by the first rotation part and holds the anode rotatably in a circumferential direction.SELECTED DRAWING: Figure 3【課題】小さな焦点サイズで従来よりも高出力のＸ線を得ること。【解決手段】実施形態に係るＸ線ＣＴ装置は、Ｘ線管と、Ｘ線検出器と、第１の回転部と、第２の回転部とを備える。Ｘ線管は、熱電子を照射する陰極と、熱電子を受けてＸ線を発生し、撮像中心の周囲に亘って設けられる円環状の陽極と、を備える。Ｘ線検出器は、Ｘ線管の陽極によって発生されたＸ線が照射される位置に設けられる。第１の回転部は、陰極と、陽極と、Ｘ線検出器とを周方向に回転可能に保持する。第２の回転部は、第１の回転部に保持され、陽極を周方向に回転可能に保持する。【選択図】 図３
