1. A pattern model positioning method in image processing, comprising the following steps for performing positioning with higher accuracy than at an initially given position upon searching out of an image to be searched and positioning an object to be searched that is similar to a pre-registered image by use of a pattern model corresponding to a registered image: extracting a contour from the registered image which utilizes a contour extracting device; constructing a pattern model of the registered image which utilizes a pattern constituting device, comprising setting a plurality of reference points on the extracted contour, and also a corresponding point search line having a predetermined length is allocated to each reference point, and wherein the corresponding point search line passes through each reference point and is orthogonal to the extracted contour; acquiring an image to be searched which utilizes an image input device, and also arranging the pattern model so that the pattern model is superimposed on the image to be searched in accordance with an initial position included in the image to be searched and the pattern model corresponding to the registered image which utilizes a fine positioning device; finding a corresponding edge point on the image to be searched corresponding to a reference point of each corresponding point search line of the pattern model out of each pixel in the image to be searched that is positioned as superimposed on the corresponding point search line upon superimposing the pattern model on the initial position on the image to be searched, which utilizes the fine positioning device; and taking a distance between each corresponding edge point and a contour including the reference point corresponding to the corresponding edge point as an evaluation value, and performing fine positioning with accuracy higher than accuracy in the given initial position such that an accumulated value of the evaluation values becomes minimal, which utilizes the fine positioning device, and wherein the step of extracting the contour from the registered image includes the steps of: extracting a plurality of edge points from the registered image which utilizes the contour extracting device; coupling adjacent edge points among the extracted plurality of edge points, to create a continuous chain which utilizes a chain creating device; and creating a segment by respectively approximating one or more chains by means of a line and/or a circular arc, and regarding aggregation of the segments as a contour which utilizes a segment creating device, and wherein a pre-set margin is set at the edge of the segment upon setting the reference point on the contour, and the reference point is set in a region excluding the margin portion.