A navigation apparatus 1 includes: a storage portion 21 that stores three-dimensional image data of an examinee that is previously acquired an organ extracting portion 22 that extracts a predetermined organ from the three-dimensional image data a first region designating portion 23 that designates a tumor 60 in the three-dimensional image data a blood vessel extracting portion that extracts blood vessels that are inside the organ from the three-dimensional image data a blood vessel classifying portion 25 that classifies the blood vessels into either arteries or veins and a second region extracting portion 26 that, on the basis of three-dimensional image information of the blood vessels, extracts a tumor resection region which is a region that is classified based on anatomical features of the organ and which includes a tumor 60.
