In order to generate an X-ray CT image with optimal quality for each part and each region of an object when scanning the object across a plurality of parts using a plane detector, there is provided an X-ray CT apparatus including smoothing means 230 and filtering means 250 for generating a convolution filter on the basis of feature amounts of projection data output from the X-ray detector 12 and superimposing the convolution filter on the projection data, reconstruction means 200 for generating an X-ray CT image of the object by performing a reconstruction operation on the projection data on which the convolution filter is superimposed, and image display means 280 for displaying the image generated by the reconstruction means 200.