A user authentication device, comprising: a card reader configured to obtain a face image stored in a card when the card is recognized, wherein the face image is encoded in the card ; an infrared light source configured to emit infrared light toward a user; an infrared camera configured to obtain an infrared image comprising a facial region of the user; a color camera configured to obtain a color image comprising the facial region of the user; a storage ; and a controller configured to: store the obtained infrared image, the obtained color image and the obtained face image in the storage temporarily ; perform a liveness test based on the obtained infrared image; when a result of the liveness test is determined to be successful, extract a first facial feature from the encoded face image obtained through the card reader, extract a second facial feature from at least one of the obtained color image and the obtained infrared image, and determine a result of face authentication based on a result of comparing the first facial feature and the second facial feature; and when the result of the face authentication is determined, perform a control to delete the obtained infrared image, the obtained color image and the obtained face image from the storage . a card reader configured to obtain a face image stored in a card when the card is recognized, wherein the face image is encoded in the card ; an infrared light source configured to emit infrared light toward a user; an infrared camera configured to obtain an infrared image comprising a facial region of the user; a color camera configured to obtain a color image comprising the facial region of the user; a storage ; and a controller configured to: store the obtained infrared image, the obtained color image and the obtained face image in the storage temporarily ; perform a liveness test based on the obtained infrared image; when a result of the liveness test is determined to be successful, extract a first facial feature from the encoded face image obtained through the card reader, extract a second facial feature from at least one of the obtained color image and the obtained infrared image, and determine a result of face authentication based on a result of comparing the first facial feature and the second facial feature; and when the result of the face authentication is determined, perform a control to delete the obtained infrared image, the obtained color image and the obtained face image from the storage . store the obtained infrared image, the obtained color image and the obtained face image in the storage temporarily ; perform a liveness test based on the obtained infrared image; when a result of the liveness test is determined to be successful, extract a first facial feature from the encoded face image obtained through the card reader, extract a second facial feature from at least one of the obtained color image and the obtained infrared image, and determine a result of face authentication based on a result of comparing the first facial feature and the second facial feature; and when the result of the face authentication is determined, perform a control to delete the obtained infrared image, the obtained color image and the obtained face image from the storage . <EOS>