PROBLEM TO BE SOLVED: To reduce an exposure dose.SOLUTION: In an IVR-CT apparatus, a first support part supports a first X-ray tube and a first X-ray detector for detecting X-rays which are radiated from the first X-ray tube and pass through an analyte. A second support part supports a second X-ray tube and a second X-ray detector for detecting X-rays radiated from the second X-ray tube in such a manner that they are made to face each other across an imaging space where a bed is moved, and moves the second X-ray tube and the second X-ray detector on a circular orbit surrounding the imaging space. A setting part sets a region of interest on an X-ray image generated on the basis of the X-rays detected by the first X-ray detector. A calculation part calculates an angle formed between a trajectory of the X-rays which are radiated from the first X-ray tube and pass through a location corresponding to the region of interest when taking an X-ray image and a scanning surface of the X-rays radiated from the second X-r
