An authenticating system according to the present invention has a characteristic structure of which an authenticating section 32 of a note type PC 10 and an authenticating section 42 of a battery 20 are directly connected through I/O ports 51 and 61, respectively. Thus, the authenticating system according to the present invention can be relatively easily accomplished using a conventional system. The present invention can be applied to a system that is composed of a plurality of electronic devices that perform an authenticating process.