To provide an X-ray CT apparatus capable of acquiring information on energy of X-rays generated by an X-ray generating apparatus, an X-ray CT apparatus (100) comprises: an X-ray generating apparatus for generating X-rays and emitting the X-rays toward a subject; a first X-ray detector having a plurality of X-ray detection channels for detecting the X-rays emitted from the X-ray generating apparatus; a second X-ray detector for detecting the X-rays emitted from the X-ray generating apparatus in order to acquire information on energy of the X-rays emitted from the X-ray generating apparatus; and an X-ray energy information identifying section for identifying information on energy of the X-rays emitted from the X-ray generating apparatus based on the information detected by the second X-ray detector.