High-speed full document retrieval method and system capable of providing result of retrieval within practically acceptable short search time. Upon registration of documents in a document database, condensed texts are created by decomposing each of textual character strings of the documents to be registered into fragmental character strings in dependence on character species and by checking mutual inclusion relations existing among the fragmental character strings. A component character table is created in which characters occurring in each of the condensed texts are registered without duplication. The condensed texts and the component character table are registered in the data base together with the texts of the documents to be registered. Upon retrieval of a document containing a search term designated by a user, a component character table search is first executed to extract those documents which contain all species of characters constituting the search term by consulting the component character table, and subsequently a condensed text search is executed by consulting the condensed texts of the documents. Finally, a text body search is executed for extracting a document which satisfies query condition imposed on the search term by consulting the texts of the documents extracted through the component character table search and the condensed text search.