When X-ray CT imaging is performed with a part located close to a front of a head as the imaging region, using the turning mechanism and the distance changing mechanism, the turning controller causes the X-ray generator and the X-ray detector to turn around the head while locating the imaging region therebetween, and causes the X-ray detector to turn along a go-around orbit, in which the X-ray detector comes close to the imaging region with respect to a front side of the head and moves away from the imaging region with respect to a rear side, by changing a distance between the X-ray detector and the center of the imaging region.
