AUTHENTICATION DEVICE, AUTHENTICATION METHOD, AND AUTHENTICATION PROGRAM

An authentication apparatus includes: an acquisition unit that acquires an image; a detection unit that performs face detection of the image; a collation unit that collates, for each face region obtained by the face detection, a feature amount of the face region with a feature amount of a face of a legitimate user included in predetermined registration data; a presentation unit that presents, when the face region obtained by the face detection includes the face of the legitimate user and a face of a third party other than the legitimate user, an aiming frame with which aim of capturing of an image of the face of the legitimate user is to be aligned on the image; and a continuation control unit that continues continuous authentication after logon when a degree of matching between the face region detected by the face detection and the aiming frame satisfies a predetermined condition.