Abstract: An X-ray CT apparatus according to the present invention comprises a plurality of X-ray generating means which generate X-rays, surround a measuring object, are arranged on a circle with the measuring object at the center, and are relatively movable with respect to the measuring object, a detector which surrounds the measuring object, is arranged on a circle with the measuring object at the center, is relatively movable with respect to the measuring object, and detects X-rays emitted from the X-ray generating means and transmitted through the measuring object, and X-ray generation controlling means which selects use/non-use of each of the X-ray generating means, and a mode setting directing means for directing a desired operation mode with respect to the X-ray generation controlling means.