BIOMETRIC AUTHENTICATION DEVICE

A start switch device 1 serving as a biometric authentication device comprises a control unit 5 which is configured so that if it is determined that a read image 22 read by a biometric sensor 2 for reading a user's biometric information 23 is unsuitable for use in biometric authentication, the control unit 5 does not carry out biometric authentication and instead outputs a notification signal S4 for causing a notification device to issue a notification that the read image 22 is unsuitable for use in biometric authentication. The start switch device 1 allows operational burden to be minimized.