An X-ray computed tomographic apparatus includes an X-ray tube which generates X-rays, an X-ray detector which detects X-rays transmitted through a subject to be examined, a reconstruction device which reconstructs an image on the basis of an output from the X-ray detector, a scan plan execution processing unit which generates the data of a scan planning window including a timing chart which expresses a scan sequence including a plurality of scan elements corresponding to a plurality of scan conditions as a temporal change in tube current or dose index, and a display device which displays a scan planning window on the basis of the data.