A biometric authentication device comprising: a biometric authentication input unit configured to obtain biometric information from a user; a verification characteristic data extracting unit configured to create verification characteristic data from the biometric information; a verification processing unit configured to verify registered characteristic data registered in a storage unit with the verification characteristic data; a true user determining unit configured to determine whether the user is a true user from a verification result by the verification processing unit; a re-authentication permitting unit configured to permit execution of re-authentications which obtain a plurality of the verification characteristic data up to a predetermined number of times when the user is determined to not be the true user; a storage area control unit configured to manage the plurality of verification characteristic data in group units by storing the plurality of verification characteristic data in an existing group or by creating a new group and storing the verification characteristic data therein, when the user is determined to not be the true user; a false user determining unit configured to determine that the user is a false user when the number of groups exceeds an upper limit number; and a re-authentication limiting unit configured to limit the execution of the re-authentications by the user when the user is determined to be the false user; wherein the storage area control unit is configured to represent a level of similarity between the verification characteristic data and verification data stored in an existing group as numerical value data, and is configured to create the new group and to store therein verification characteristic data that is judged as not similar by comparing the numerical value data with a predetermined threshold, and to store verification characteristic data that is judged as similar in any of an existing group. a biometric authentication input unit configured to obtain biometric information from a user; a verification characteristic data extracting unit configured to create verification characteristic data from the biometric information; a verification processing unit configured to verify registered characteristic data registered in a storage unit with the verification characteristic data; a true user determining unit configured to determine whether the user is a true user from a verification result by the verification processing unit; a re-authentication permitting unit configured to permit execution of re-authentications which obtain a plurality of the verification characteristic data up to a predetermined number of times when the user is determined to not be the true user; a storage area control unit configured to manage the plurality of verification characteristic data in group units by storing the plurality of verification characteristic data in an existing group or by creating a new group and storing the verification characteristic data therein, when the user is determined to not be the true user; a false user determining unit configured to determine that the user is a false user when the number of groups exceeds an upper limit number; and a re-authentication limiting unit configured to limit the execution of the re-authentications by the user when the user is determined to be the false user; wherein the storage area control unit is configured to represent a level of similarity between the verification characteristic data and verification data stored in an existing group as numerical value data, and is configured to create the new group and to store therein verification characteristic data that is judged as not similar by comparing the numerical value data with a predetermined threshold, and to store verification characteristic data that is judged as similar in any of an existing group.