A communication apparatus that is installed in a mobile unit, comprising: acquisition means that acquires positional information that indicates a current position of said communication apparatus and traveling direction information that indicates a traveling direction of said mobile unit; reception means that receives, from a transmission origin device of packets, packets that contain forwarding information that indicates a position of said transmission origin device and a position of a transmission destination for specifying the transmission destination of the packets; judgment means that, based on said positional information and said forwarding information, judges whether said current position is contained within an area from the position of said transmission origin device up to the position of said transmission destination, and when said current position is determined not to be contained within said area, prevents forwarding of said packets; correction means that, when it has been determined by said judgment means that said current position is contained within said area, extracts, as a corrected position, a position specified based on said traveling direction among positions on a circle that is separated from said current position by a remaining distance between the position of said transmission destination and said current position; and transmission means that changes the position of said transmission destination indicated by the forwarding information of said packets to said corrected position, and moreover, that changes the position of said transmission origin device indicated by said forwarding information to said current position, and transmits packets that contain the forwarding information that follows said changes. acquisition means that acquires positional information that indicates a current position of said communication apparatus and traveling direction information that indicates a traveling direction of said mobile unit; reception means that receives, from a transmission origin device of packets, packets that contain forwarding information that indicates a position of said transmission origin device and a position of a transmission destination for specifying the transmission destination of the packets; judgment means that, based on said positional information and said forwarding information, judges whether said current position is contained within an area from the position of said transmission origin device up to the position of said transmission destination, and when said current position is determined not to be contained within said area, prevents forwarding of said packets; correction means that, when it has been determined by said judgment means that said current position is contained within said area, extracts, as a corrected position, a position specified based on said traveling direction among positions on a circle that is separated from said current position by a remaining distance between the position of said transmission destination and said current position; and transmission means that changes the position of said transmission destination indicated by the forwarding information of said packets to said corrected position, and moreover, that changes the position of said transmission origin device indicated by said forwarding information to said current position, and transmits packets that contain the forwarding information that follows said changes.