1. An image collating apparatus, comprising: partial image feature value calculating means for calculating, on each of a plurality of partial area images set in an image, a value reflecting a pattern of the image of the partial area, wherein said partial image feature value is one of three different values and wherein said one of three different values respectively represent that said partial area image has a pattern extending along the vertical direction, a pattern extending along the horizontal direction and other pattern, and outputting the value as a partial image feature value; maximum matching score position searching means for searching, for each of a plurality of partial area images set in one of two images, for a maximum matching score position of the other of the two images, which is a position of a partial area image having the maximum matching score with the partial area image; similarity score calculating means for calculating a similarity score between the two images and outputting an image similarity score, using information related to that partial area of which positional relation amount is within a prescribed range, said positional relation amount representing positional relation between a reference position, for each of said partial areas, for measuring a position of the partial area within said one image, and said maximum matching score position corresponding to the partial area searched out by said maximum matching score position searching means; and determining means for determining whether said two images match or not, based on said image similarity score applied thereto; wherein scope of said the other image searched by said maximum matching score position searching means is selected and determined from among a plurality of partial areas set in said the other image in accordance with said partial image feature value of the partial area image set in said one image.