A biometrics authentication device, which uses blood vessel images of a human body to perform individual authentication, performs verification processing according to a detected body temperature. A temperature sensor, which detects the temperature of a body, is provided in a blood vessel image capture device. The temperature at the time of registration of a blood vessel image is stored together with the blood vessel image, and the temperature of the body at the time of use (at the time of verification) is detected; the temperature difference at the time of registration and at the time of use is reflected in the verification processing, and when there is a verification error, the cause of the verification error is judged from the temperatures at the time of registration and at the time of use. Whether a verification error is due to temperature can be easily distinguished.