An X-ray CT apparatus comprises an X-ray generation device which generates X-rays, an X-ray detector which detects the X-rays having passed through a subject and outputs projection data, an imaging control device which controls the X-ray generation device and the X-ray detector so as to collect projection data, an image reconstruction device which reconstructs image data from the projection data, an image display device which displays an image on the basis of the image data, an image selection information addition device which adds, to the image data, the image selection information for the image data, an image selection device which judges presence/absence of an image analysis process on the basis of the image selection information and selects the image data, and an image analysis processing device which performs the image analysis process on the basis of the image data-selected by the image selection device.