A three-dimensional image display apparatus emphasizes display of a particular portion using the volume rendering method, where a volume image constructed by aligning a plurality of tomograms is shaded and projected on a predetermined projection plane to produce a 3D image. A volume rendering method is used where, in an algorithm for shading, virtual light beams are radiated from a virtual light source set outside the volume image, and pixel values on the projection plane are calculated based on reflectivity and density gradient of light beams at the respective pixels on the projection plane. At a luminescence ratio allocating area, a luminescence ratio is allocated for amplifying light beams entering pixels representing a particular object to be emphasized. The thus-allocated luminescence ratio is added as a parameter of the shading calculation in the volume rendering method and is used for calculation of pixel values on the projection plane.