A packet transmitting apparatus according to the present invention includes a plurality of ports. When the same unlearned packets have arrived at the plurality of ports, the packet transmitting apparatus judges through packet processing section that the first arrived one of the packets is a previous arrival packet. Then, through previous arrival group judging section, the packet transmitting apparatus selects from the plurality of ports a plurality of ports satisfying a previous arrival port condition for determining a port at which the previous arrival packet arrives as a previous arrival port. The packet transmitting apparatus judges the thus selected plurality of ports as the previous arrival ports having an equal previous arrival characteristic of packets, and includes the ports in a previous arrival port group.