An X-ray computed tomography apparatus according to an embodiment includes an X-ray detector, a data-acquisition module and a reconstruction module. In the X-ray detector, a plurality of X-ray detection elements are arranged in a channel direction and a column direction. The data-acquisition module includes a plurality of data-acquisition circuits and a plurality of output modules. A plurality of systems of at least the data-acquisition circuits among the X-ray detection elements and the data-acquisition circuits are disposed in parallel per element of the X-ray detection elements in a center vicinity. Each of the output modules outputs digital data obtained via the data-acquisition circuits. The reconstruction module reconstructs a medical image, based on the output digital data.
