According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube and an X-ray detector. The X-ray tube generates X-rays. The X-ray detector includes a first detection area detecting the X-rays and a second detection area detecting the X-rays. The first detection area includes a first scintillator having a first fluorescence decay time, the second detection area includes a second scintillator having a second fluorescence decay time shorter than the first fluorescence decay time. The second detection area is arranged at both ends of the first detection area with respect to a channel direction.
