1. A law retrieval system constituted by connecting a user information transmitter-receiver by which a user transmits a retrieval condition and receives a retrieval result and a law retrieval server for performing retrieval processing in sequence in accordance with the retrieval condition received from said user information transmitter-receiver, via a communication network, and by connecting data storage means, in which laws, judicial cases, and data required for retrieval are accumulated, to said law retrieval server, wherein said data storage means includes a constitution and statute database in which data of the constitution, laws, government orders and ministerial orders, and the like is accumulated, a judicial case database in which data of judicial cases is accumulated, and at least one database out of a meta-keyword database constructed by associating non-retrieval keywords such as slang words with retrieval keywords adequate for replacing the non-retrieval keywords, a verb and object database constructed by associating verbs and objects related to each other and associating retrieval keywords related to combinations of them, and an aid flow database previously constructed as aid flowcharts by predicting information gathering query patterns for cases, and wherein said law retrieval server includes, in correspondence with said each database, at least one retrieval processing means out of meta-keyword retrieval processing means, when a received keyword is a non-retrieval keyword, for reading an associated retrieval keyword from said meta-keyword database to perform retrieval processing, verb and object retrieval processing means for reading a retrieval keyword associated with a combination of a received verb and object from said verb and object database to perform retrieval processing, and aid flow retrieval processing means, when a retrieval pattern by a received retrieval keyword matches a pattern of an aid flowchart, for transmitting requests for additional information in sequence in accordance with a flow of the aid flowchart.