Abstract: An image processing device acquiring pseudo projection data by calculation when a virtual metallic body having a predetermined X-ray absorption coefficient is set in a photographic region of X-ray CT photography in a pseudo manner based on projection data, and the image processing device reconstructing the pseudo projection data to acquire pseudo CT image data. The image processing device acquires luminance (virtual metallic body luminance) of a virtual metallic body in the pseudo CT image data, and specifies a position of a metal equivalent region having luminance corresponding to the virtual metallic body luminance in normal CT image data. The image processing device acquires correction projection data by performing correction processing to the luminance of the metal equivalent region in the normal projection data, and the image processing device reconstructs the correction projection data to acquire correction CT image data.