1. A circuit pattern comparison apparatus for extracting portions matched to a designated predetermined search pattern from an object of comparison represented by a circuit network having a set of nodes and node-to-node arcs or links, comprising: search pattern editing means for schematically describing said designated predetermined search pattern having a plurality of nodes; comparison order designating means for designating a comparison order of the nodes contained in the designated predetermined search pattern; search code synthesizing means for synthesizing at least one search code by subjecting, to code conversion, said designated predetermined search pattern schematically described by said search pattern editing means; comparing means for comparing the designated predetermined search pattern to the object of comparison utilizing the at least one search code; and extracting means for extracting at least one portion of the object of comparison matched to said designated predetermined search pattern.