Image collation system and image collation method

There are provided a three-dimensional data input means for input the three-dimensional data of an object, a reference image storing unit for storing a reference image of at least one object, a pose candidate deciding means for generating a pose candidate that is a candidate for the pose of the object, a comparison image generating means for generating a comparison image close to the reference image while projecting the three-dimensional data onto a two-dimensional image in accordance with the pose candidate, and an image comparing means for performing comparison based on either a distance value or similarity degree between the reference image and the comparison image. This allows comparison or search to be performed with high accuracy even when the reference image of the object is captured under different conditions such as pose and illumination, even when no three-dimensional object model of the object can be obtained in advance, or even when only one or few reference images exist.