To obtain a password authenticating method which is effective to prevention against the repetition of illegal use of an information system by the mechanical deciphering of a password.

This is a method for managing a password used to authenticate the legal right to access and the password is composed of a fixed password part 20 consisting of previously registered characters or symbols and a cyclic password part 30 which is used by circulating previously registered candidate characters or symbols in a fixed direction. As the cyclic password part 30, candidates of characters or symbols are circulated according to the frequency of authentication and used.