Provided are a biometric authentication device and a control device whereby deterioration of authentication precision is not incurred. A biometric authentication device comprises: an image sensor which detects biometric information and external light an external light detection unit which sets an external light level on the basis of the external light which the image sensor has detected and an authentication unit which changes according to the external light level the priority of the user identification using the biometric information which the image sensor has detected, and authenticates a user at the post-change priority using the biometric information which the image sensor has detected.
