Patent ID: 8816818

Claim:
A biometric authentication device, comprising: a memory; and a processor coupled to the memory and configured to: acquire input biometric information of a user, and generate input biometric data representing the input biometric information; store registered biometric data representing registered biometric information of at least one registered user who is registered in advance; execute either a first verification process or a second verification process, wherein the first verification process calculates a first degree of similarity representing a degree of similarity between the input biometric information and the registered biometric information, and the second verification process calculates a second degree of similarity representing the degree of similarity between the input biometric information and the registered biometric information by verifying the input biometric information against the registered biometric information with higher precision than with the first verification process; authenticate, when the first or the second degree of similarity takes a value larger than a predetermined verification assessment threshold value, the user as the registered user corresponding to the registered biometric information; store the first degree of similarity calculated by the first verification process with a correlation with the registered biometric data representing the registered biometric information verified against the input biometric information; and change, by referring to the first degree of similarity correlated with the registered biometric data, when an authentication success rate indicating a rate of authenticating the registered user as the user is determined as showing an over-time reduction, the first verification process to the second verification process for execution.