A computer-readable recording medium storing an authentication program for causing a computer to execute an authentication process, the authentication process includes: extracting a plurality of face information from an image acquired; when the plurality of face information include both first face information registered in authentication information and second face information not registered in the authentication information, registering the second face information in the authentication information; and if new face information extracted from new image is the second face information stored in the authentication information, determining that an authentication for the new face information is successful.