1. An image recognition method comprising: performing the following steps on at least one processor (I) taking a first image encompassing an entire character, the first image composed of plural elements having different shapes; (II) extracting said plural elements having different shapes in said first image to obtain a second image, in which each of said plural elements is enclosed by an inner rectangular frame and a shape of each inner rectangular frame is individually determined based upon a shape of the element the inner rectangular frame surrounds; (III) forming a composite image with respect to a combination of said inner rectangular frames in said second image; (IV) calculating a characteristic amount of said elements included in said composite image; (V) inputting said characteristic amount in a back-propagation network, in which learning about a reference character(s) to be included in said first image has already finished, to provide a degree of agreement between the characteristic amount of said composite image and the reference character; and (VI) determining said composite image having a highest degree of agreement between the characteristic amount of said composite image and the reference character from results obtained by repeating the steps (III) to (V) with respect to different combinations of said inner rectangular frames in said second image, to output it as a recognition data.