An image processing device that rotates an image according to the inclination of a line segment included in the image, includes an evaluation unit 106 that evaluates a plurality of line segments whose inclinations are different, on the basis of each of a plurality of different decision standards, and a selection unit 106 that selects, on the basis of the results of the plurality of evaluations, from among the plurality of line segments, a line segment on the basis of which the image is to be rotated.