1. A matching point extracting apparatus for extracting, in synthesizing plural images, the matching points of said plural images, comprising: A) template image data formation means for entering plural image data each corresponding to an image of an image frame, taking an image represented by the image data corresponding to an arbitrary image frame among thus entered image data of plural image frames as a reference image, extracting the image data, corresponding to a partial area in said reference image, as a template image and outputting the template image data corresponding to thus extracted template image: B) matching candidate extraction means for comparing the value of each pixel data constituting the template image data outputted by said template image data formation means with the value of each pixel data constituting the image data corresponding to each of search images which are the images, other than the reference image, of the image data of the plural image frames entered into said template image data formation means, determining the number of pixel data showing differences smaller than a predetermined value, calculating the similarity of said search image to said template image according to said number of pixel data, extracting said search image showing maximum in said similarity as a matching candidate for said template image, and outputting said matching candidate together with similarity data indicating said similarity; C) decision means for judging, based on the similarity data outputted by said matching candidate extraction means, whether the pixel data constituting said template image satisfy a specified condition; and D) template image changing means adapted, in case said decision means identifies that the pixel data constituting said template image satisfy said specified condition, for changing the shape of the template image represented by the template image data outputted by said template image formation means and outputting such changed template image to said matching candidate extraction means.