1. A pattern collating device for collating an examination target graphic with a model graphic, comprising: feature point pair formation means for making feature point pairs, each of which is composed of a feature point in said examination target graphic and a feature point in said model graphic which correspond to each other, said feature point in said examination target graphic which composes each of said feature point pair being selected from points which indicate feature of said examination target graphic, said feature point in said model graphic which composes each of said feature point pair being selected from points which indicate feature of said model graphic: probability calculation means for calculating a probability that a number of feature point pairs between an arbitrary graphic and said model graphic is not less than a number of said feature point pairs between said examination target graphic and said model graphic, similarity calculation means for calculating similarity between said examination target graphic and said model graphic on the basis of said probability.