An X-ray CT apparatus 1 for radiating X-ray to a subject P so as to scan the subject P and reconstructing a image within the subject P based on an obtained projection data comprises an image generating unit and a blood-flow image generating unit 24e. The image generating unit generates the image based on the projection data in a state in which a concentration of a contrast medium in a myocardial portion of a subject P continuously injected the contrast medium can be considered to be constant. The blood-flow image generating unit 24e generates a blood flow image by removing components of a myocardial tissue from a portion of a myocardial region of the image generated by the image generating unit.
