PROBLEM TO BE SOLVED: To provide an image processor capable of enhancing image diagnosing ability.SOLUTION: A storing section 2 stores a three dimensional nerve image relating to the nerve tissue of a brain and a three dimensional tumor image relating to tumor of the brain. A synthetic image generating part 4 generates a synthesized image of the nerve image and the tumor image. A nerve index value deciding part 5 decides an index value relating to an anatomical running condition of a nerve region derived from the nerve image to the tumor region derived from the tumor image of the synthesized image. A display image generating part 6 generates a two dimensional information image in which an information value according to the decided index value is allocated to the tumor region included in synthesized image based on the synthesized image. A display part 7 displays the generated information image.
