5. The computer-readable recording medium according to claim 3 , wherein the hierarchy retrieval automaton makes state transition to the subordinate hierarchical node, if an end symbol of the start tag is given when state transition has been made to an end node of the series of nodes.
6. The computer-readable recording medium according to claim 5 , wherein the hierarchy retrieval automaton has a series of nodes representing the hierarchical name of the subordinate hierarchical node between the node representing the start symbol and the superior hierarchical node, and if a character string is given when state transition has been made to the node representing the start symbol, the hierarchy retrieval automaton makes state transition to the series of nodes until a hit-missing character appears.