A photon-counting X-ray computed tomography (CT) apparatus of an embodiment includes photon-counting CT detection circuitry, integral CT detection circuitry, switching circuitry, and a feedback capacitance. Photon-counting CT detection circuitry outputs count values for respective energy bins, based on voltage pulses output from a feedback capacitance with electric charges output from an X-ray detection element configured to detect incident X-rays. Integral CT detection circuitry outputs an integral value, based on the voltage pulses output from the feedback capacitance with the electric charges output from the X-ray detection element. Switching circuitry switches between a case of transmitting the electric charges output from the X-ray detection element to the photon-counting CT detection circuitry and a case of transmitting the electric charges output from the X-ray detection element to the integral CT detection circuitry. The feedback capacitance is connected with the photon-counting CT detection circuitry and the integral CT detection circuitry in parallel.