An image information processing apparatus generating three-dimensional volume data corresponding to a sample on the basis of two-dimensional projection data of the sample from a full circumferential direction acquired by an image capturing apparatus comprising an irradiation unit irradiating transmittable energy onto the sample; a photo detector receiving the energy through the sample; and a rotator rotating the sample is provided. The apparatus includes correcting means correcting pixels of said projection image data depending on an inclination angle of the rotator determined on the basis of a rotation axis of the rotator and an irradiation axis of the irradiation unit; filtering means giving a prescribed filtering processing to projection image data pixels having been corrected by the correcting means; and voxel calculating means calculating voxels of the volume data using the projection image data pixels having been given the filtering processing and depending on the inclination angle of the rotator.