An image processing device, that is configured to acquire CT image data by reconstructing projection data, the projection data being acquired by performing X-ray CT photography of a region including a metallic body (91M, 93M) in a subject, the image processing device comprising: a simulated projection data acquisition unit that is configured to compute simulated projection data by calculation when a virtual metallic body (91VM, 93VM) having a predetermined X-ray absorption coefficient is arranged in a simulation manner in a photographic region of said X-ray CT photography based on said projection data; a simulated CT image data generator that is configured to reconstruct said simulated projection data in order to generate simulated CT image data; a virtual metallic body luminance acquisition unit (31 P) that is configured to acquire virtual metallic body luminance that is luminance corresponding to said virtual metallic body (91VM, 93VM) in said simulated CT image data; a position specification unit that is configured to specify a position of a metal equivalent region having luminance corresponding to said virtual metallic body luminance in CT image data a correction processor that is configured to generate correction projection data by performing correction processing to the luminance of said metal equivalent region in said projection data, degradation of X-ray intensity due to X-ray absorption being corrected through the correction processing; and a correction CT image data acquisition unit that is configured to reconstruct said correction projection data to generate correction CT image data, wherein said X-ray CT photographic apparatus further includes a subject retention unit that retains the subject, and said virtual metallic body (91VM, 93VM) is arranged in a simulation manner in a position different from said metallic body (91M, 93M), which is determined based on positional information on said subject, the positional information on said subject being retained in said subject retention unit. a simulated projection data acquisition unit that is configured to compute simulated projection data by calculation when a virtual metallic body (91VM, 93VM) having a predetermined X-ray absorption coefficient is arranged in a simulation manner in a photographic region of said X-ray CT photography based on said projection data; a simulated CT image data generator that is configured to reconstruct said simulated projection data in order to generate simulated CT image data; a virtual metallic body luminance acquisition unit (31 P) that is configured to acquire virtual metallic body luminance that is luminance corresponding to said virtual metallic body (91VM, 93VM) in said simulated CT image data; a position specification unit that is configured to specify a position of a metal equivalent region having luminance corresponding to said virtual metallic body luminance in CT image data a correction processor that is configured to generate correction projection data by performing correction processing to the luminance of said metal equivalent region in said projection data, degradation of X-ray intensity due to X-ray absorption being corrected through the correction processing; and a correction CT image data acquisition unit that is configured to reconstruct said correction projection data to generate correction CT image data, said X-ray CT photographic apparatus further includes a subject retention unit that retains the subject, and said virtual metallic body (91VM, 93VM) is arranged in a simulation manner in a position different from said metallic body (91M, 93M), which is determined based on positional information on said subject, the positional information on said subject being retained in said subject retention unit.