To solve the problems described above, an X-ray computed tomography apparatus includes an X-ray tube, a scintillator, a photoelectric convertor, a thermal storage material, a rotating portion, a rotating mechanism, and image generating circuitry. The X-ray tube generates an X-ray. The scintillator converts the X-ray generated by the X-ray tube into light. The photoelectric convertor generates an electric signal based on the light obtained by conversion by the scintillator. The thermal storage material is attached to the photoelectric convertor, and absorbs heat. To the rotating portion, the X-ray tube, the scintillator, the photoelectric convertor, and the thermal storage material are attached. The rotating mechanism rotates the rotating portion around a subject. The image generating circuitry generates an image based on the electric signal generated by the photoelectric convertor.