When biometric information is registered, master helper data is created from user's biometric information and is saved in an IC card. When a user is registered in an authentication server, a password is created and registered in the server, the master helper data is converted to create helper data corresponding to the password, and the helper data is saved in an authentication terminal. When a user is authenticated, the authentication terminal generates an authentication password from the helper data and newly acquired user's biometric information, sends the generated authentication password to the authentication server, and the authentication server compares the authentication password with a registration password to authenticate the user.