PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus and a body position determination method which can quickly and highly accurately determine the body position of a subject lying down on a bed and improve the workflow of a CT inspection.SOLUTION: A distance measurement device 108 (depth camera) which is arranged at a prescribed measurement point such as an upper part of a scan gantry part measures a distance to each point on a subject 3 lying down on a bed 101. An arithmetic device 202 creates distance distributions in a body axis direction and a body width direction respectively from a prescribed reference point (nearest point) of the subject 3 on the basis of the measured distance information. The arithmetic device 202 determines an intermediate body position of the subject 3 on the basis of the created distance distribution in the body width direction first. Moreover, the arithmetic device 202 sets body position information determined by segmenting the intermediate body position as an imaging condition of an X-ray CT apparatus 1 on the basis of the distance distribution in the body axis direction.
