1. A pattern recognition device comprising: a catalog of a plurality of items of standard data each made up of a plurality of consecutive standard elements, said plurality of items of standard data having a predetermined correspondence to prescribed recognition data; a predetermined tree structure of data, said tree structure having a root node and a plurality of subordinate nodes, each said subordinate node corresponding to one of said standard elements; said plurality of subordinate nodes being linked by a number of parent nodes, said number of parent nodes being smaller than a number of said subordinate nodes, said parent nodes each corresponding, on average, to a plurality of mutually similar ones of said standard elements; parent distance calculating means for calculating respective parent node distances of similarity for each of a plurality of recognition elements included in inputted recognition data; parent node selecting means for selecting ones of said parent nodes based on a magnitude of said respective parent node distances of similarity; subordinate distance calculating means for calculating respective subordinate node distances of similarity for each of said recognition elements only for ones of said subordinate nodes linked to said selected parent nodes; distance storage means for storing only once, in order, at predetermined positions, said respective parent node distances of similarity, and for storing, in order, at other predetermined positions, only said respective subordinate node distances of similarity for said subordinate nodes of said selected parent nodes; and means for determining a recognition result based on said stored distances.