A packet forwarding apparatus includes: a multicast determination unit that determines whether a packet that flows through a virtual network is a multicast communication packet; a multicast mapping information storage unit; a multicast mapping unit that allocates a second multicast address to a first multicast address of a newly generated multicast communication and manages these multicast addresses as a piece of mapping information; and a packet encapsulation unit that encapsulates the packet that flows through the virtual network. The packet encapsulation unit encapsulates the multicast communication packet that flows through the virtual network by using the second multicast address.