1. An information retrieval support method for presenting candidate words to be input after an input word, comprising the steps of: storing a group of input words, that have been input as a target for the user, as sequences in a sequence database; storing a certain words in a hash database made up of keyed hashes based on the stored sequences; acquiring hashes to key the appropriate input words from the hash sequence database in response to words input by the user; calculating an index relating to words constituting the hash; and arranging the appropriate words in a word directory whose root corresponds to the keyed words in the event that the appropriate words satisfy a specified condition, and a step of outputting the created word directory.