1. A pattern model positioning method in image processing, including the following steps 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 the registered image: a first coarse search step of performing a search on the whole area of a second-reduction-ratio image to be searched, obtained by reducing the image to be searched with a second reduction ratio, by use of a first pattern model created from the registered image with the second reduction ratio; a second coarse search step of further performing a search locally on a first-reduction-ratio image to be searched or the second-reduction-ratio image to be searched, created from the image to be searched, based on a result obtained in the first coarse search step by use of a second pattern model created from the registered image with the second reduction ratio or a first reduction ratio made lower than the second reduction ratio; and the step of further performing fine positioning with accuracy higher than the first or second coarse search on a fourth-reduction-ratio image to be searched, which is created from the image to be searched and a reduction ratio of which is a fourth reduction ratio not higher than the first reduction ratio, based on a result obtained in the second coarse search step by use of a third pattern model having the fourth reduction ratio which is created from the registered image, wherein, in advance of the first coarse search step, the method includes the steps of: reducing the pre-registered image into the first reduction ratio; creating a first pattern model having the second reduction ratio which is created based on geometric information on a contour in the registered image reduced with the second reduction ratio and used in the first coarse search step, a second pattern model having the first or second reduction ratio which is created based on geometric information on a contour in the registered image reduced with the first or second reduction ratio and used in the second coarse search step, and a third pattern model having the fourth reduction ratio which is created from a fourth-reduction-ratio image to be searched and used in the fine positioning; acquiring the image to be searched and also reducing the image to be searched into the first reduction ratio; computing an edge angle image having the first reduction ratio and including edge angle information in each pixel constituting the image, by use of the first-reduction-ratio image to be searched; creating an edge angle bit image having the first reduction ratio, which is expressed by an edge angle bit indicating an angle with a pre-defined fixed width with respect to each pixel, by use of the edge angle image having the first reduction ratio; and performing an OR operation on an edge angle bit of every pixel included in an OR operation region decided in accordance with the second reduction ratio in order to create an edge angle bit reduced image having the second reduction ratio that is larger than the first reduction ratio of the edge angle bit having the first reduction ratio, to create an edge angle bit reduced image having the second reduction ratio which is made up of reduced edge angle bit data representing each OR operation region, and thereby, the method makes the following steps executable: the first coarse search step of positioning of the first pattern model having the second reduction ratio on the whole area of the edge angle bit reduced image having the second reduction ratio; the second coarse search step of performing a local coarse search on the edge angle bit image having the first reduction ratio or the edge angle bit reduced image having the second reduction ratio based on a result of the positioning in the first coarse search by use of the second pattern model corresponding to the reduction ratio; and the step of performing fine positioning based on a result of the second coarse search by use of the third pattern model for fine positioning having the fourth reduction ratio, which is between the registered image having the first reduction ratio and the registered image as an original image, and the fourth-reduction-ratio image to be searched of the registered image corresponding to the third pattern model.