A portable personal server connectable through a network with a PC connected with an external network that permits communication with the PC only when user's fingerprint information read out by means of a fingerprint authentication unit matches registered information. In order to communicate through the network, the portable personal server and the PC acquires an address, preferably using APIPA, so that the collision of address does not take place in the external network. Consequently, the portable personal server also functions as a network server on the external network. A portable personal server exhibiting high confidentiality of data and suitable for central management of data can thereby be realized.