1. A biometrics authentication system which detects characteristics of a body of a user to perform individual authentication, comprising: a detection device which detects a target portion of the body and outputs biometrics data indicating characteristics of the body; a database file which stores a set of at least two type biometrics data for each of a plurality of users, detected by the detection device and similarity information indicating existence of a similar biometric data of another user; and a control unit, at the time of authentication, first verifies one type biometrics data detected by the detection device against one type biometrics data of said two type biometric data registered in the database file, judges that similar registered one type biometrics data of another user exists in the database file by referring said similarity information when said first verify is successful, second verifies another type biometrics data of said user detected by the detection device against another type biometrics data of said user and said another user which has a similarity relationship in the database file, and identifies an individual with biometrics characteristic data for which the second verification result is satisfactory.