Abstract: The present invention is directed to configure an effective search node based on splitting, regrouping, complexity calculation, and learning information, and perform high-performance regular expression search. To this end, the present invention includes: a policy database; a regular expression extraction processor; a regular expression fragment processor that splits each of the regular expression character strings extracted by the regular expression extraction processor in accordance with a fragmentation rule; a regular expression normalization processor that generates an optimized regular expression fragment table; a cost calculation engine processor that determines a cost for each of the regular expression fragments; a decision tree generation processor that generates a decision tree based on cost information; and a pattern matching engine processor that configures a search engine.