To generate a reconstructed image suitable to characteristics of a bilaterally symmetric site and possible to an appropriate image diagnosis, a computation device: computes a back projection phase width at a rotational center and distance between the rotational center location which is a reference location and a pixel to be reconstructed according to the distance between the rotational center location and the pixel to be reconstructed, sets a function (f1) changing the back projection phase width computes a back projection phase width in the pixel to be reconstructed, substituting a value of the distance between the rotational center location and a pixel to be reconstructed in the function (f1) computes a view weighting, on the basis of the back projection phase width in the post-correction pixel to be reconstructed and a slope width of a view weighting function and reconstructs a CT image, using the view weighting.
