1. An apparatus for processing information about a network including a plurality of nodes, wherein m attributes (m represents an integer of 2 or more) assignable to each of said nodes are defined depending on the relationship to another node which can be connected to said each of the nodes, said apparatus comprising: identifier generating means for converting attributes assigned to each of n nodes (n represents an integer of 3 or more) per relationship to the other node connected thereto into numerical values with respect to motifs extracted from said network as predetermined patterns of the connected relationship of the n nodes, and generating identifiers identifying said motifs using said numerical values.