An authentication device that authenticates an individual by using features of a biological object includes an input device 2 to place the biological object thereon, a plurality of image capture devices 9 that capture the biological object, an authentication processing unit 10 that processes images captured by the plurality of image capture devices, a plurality of light sources 3 to capture the features of the biological object and the biological object, and a storage device 14 that stores first feature data registered in advance. The authentication processing unit 10 includes a checking processing unit that checks second feature data representing the features of the biological object captured by the image capture devices with each of the first feature data and a biological position/shape detection unit that detects position/shape information of finger such as flexure, floating, bending, and the like of finger, and the plurality of light sources are arranged in a front part, a lower part, and a side part of the device with respect to the biological object, and, on the basis of a detection result obtained by the biological position/shape detection unit, controls on/off states of the plurality of light sources to switch feature values used in authentication.