An X-ray CT apparatus according to the embodiment executes an imaging according to an imaging protocol including one or more image elements corresponding to an imaging type. The X-ray CT apparatus includes an X-ray source, an X-ray detector and processing circuitry. The X-ray source radiates an X-ray. The X-ray detector detects the X-ray. The processing circuitry merges, when first and second imaging protocols are set, first and second imaging elements, respectively included in the first and second imaging protocols, corresponding to same imaging type into a single third imaging element, thereby generating a third imaging protocol including the third imaging element.