PROBLEM TO BE SOLVED: To provide an image processor capable of detecting an abnormal part with high accuracy by clearly distinguishing an abnormal part protruding from a mucosal surface from a foam, an image processing method, and image processing program.SOLUTION: An image processor 1 includes a contour extraction part 110 for extracting a plurality of contour pixels from an image acquired by imaging the inside of a lumen of an organism, a feature quantity calculation part 130 for calculating feature quantity based on each pixel value of a plurality of contour pixels and a positional relation among the plurality of contour pixels, and an abnormal part detection part 140 for detecting an abnormal part on the basis of the feature quantity.
