An index-value detecting unit detects an index value that indicates a contrast medium density in a Region Of Interest (ROI) set on an image reconstructed during a scan. A switch-timing detecting unit detects an inflection point appearing on a curve that indicates temporal variations in the contrast medium density in the ROI, based on an index value detected by the index-value detecting unit. An imaging control unit then performs control so as to skip the rest of a scanning plan in execution and to start the next scanning plan when the switch-timing detecting unit detects an inflection point.
