To provide a network connection communication apparatus that causes no confusion to a network even when the same IP address as that of other apparatus is registered.

A flowchart for explaining an IP address confirmation processing includes: steps ST3, ST6 of broadcasting an ARP packet onto the network 150 by using an IP address registered in its own apparatus at starting up of power or at registration of the IP address of its own apparatus (steps ST1, ST4); a step ST8 of thereafter discriminating whether or not a MAC address in an ARP response is the same as a MAC address of its own apparatus upon the receipt of the ARP response including the same IP address as the IP address having been registered by its own apparatus from the network 150 (ST7); and a step ST9 of displaying a fact that there exists another apparatus having the same IP address as that of its own apparatus on a display section 7 when the above MAC addresses differ from each other.