An X-ray data processing apparatus for processing X-ray data that is obtained by simultaneously measuring X-rays of multiple wavelengths. The apparatus includes a management unit 210 to receive and manage X-ray data that is detected by a detector, a calculation unit 230 which calculates a detection amount of charge sharing events in lower energy side data caused by higher energy X-ray, based on the higher energy side data obtained using a threshold value on a higher energy side and the lower energy side data obtained using a threshold value on a lower energy side of the received X-ray data, and a correction unit 250 to reconfigure the lower energy side data using the calculated detection amount. The apparatus can remove a residual image of an X-ray on a higher energy side which remains in data on a lower energy side.