A PC (1) comprises: a tomographic image information acquisition unit (6) a memory (9) a volume rendering calculation unit (13) a display (2) a mouse (4) and a voxel label setting unit (18). The tomographic image information acquisition unit (6) obtains tomographic image information. The memory (9) stores voxel information for the tomographic image information. The volume rendering calculation unit (13) samples voxel information in a direction perpendicular to the line of sight on the basis of the voxel information. The display (2) displays calculation results from the volume rendering calculation unit (13). The mouse (4) enters cutting instructions for a liver (22) displayed on the display (2). The voxel label setting unit (18) displays the status of the liver (22) after cutting using the cutting instructions by the mouse (4) and displays blood vessels (23) inside the liver (22) included in a cutting section (C) in a pre cut state even after cutting.
