Abstract: Biometric information registered for each user is held, user information being a plurality types of attribute information associated with each user is held, a possibility that the user requests authentication is predicted and a predicted value is calculated for each user by using the plurality types of attribute information contained in the held user information. When biometric information for an authentication request is accepted, the accepted biometric information is matched against the biometric information for a plurality of users determined based on calculated predicted values, and it is determined based on the result of the matching whether a person having entered the accepted biometric information is authenticated as the user.