A route information relay method for relaying route information indicating a route through which a packet is transmitted to a destination wireless terminal by each wireless terminal when the wireless terminal relays the packet based on the route information, the method comprising: at each wireless terminal (x), a route information receiving step of receiving the route information included in a packet received from a first wireless terminal (d) adjacent to the wireless terminal (x) and indicating a correspondence relationship between a packet destination node and a packet relay node, and storing the received route information in the receiving wireless terminal; a quality information obtaining step of obtaining quality information indicating quality of a route indicated by the received route information and storing the obtained quality information in correspondence with a packet destination node and a packet relay node with respect to the wireless terminal in a route information table; a determining step of determining, at every predetermined period, whether a plurality of pieces of route information indicating the same wireless terminal as packet destination node are received based on the route information table; a selecting step of selecting, when it is determined that a plurality of pieces of route information indicating the same wireless terminal as the packet destination node are received, one piece of route information corresponding to a piece of quality information indicating a highest quality among the plurality of pieces of route information; and a relay step of generating a packet including the selected piece of route information and relaying the generated packet to a second wireless terminal (v; z) adjacent to the wireless terminal (x); wherein the selecting, the generating and the relaying are also performed at the predetermined period. at each wireless terminal (x), a route information receiving step of receiving the route information included in a packet received from a first wireless terminal (d) adjacent to the wireless terminal (x) and indicating a correspondence relationship between a packet destination node and a packet relay node, and storing the received route information in the receiving wireless terminal; a quality information obtaining step of obtaining quality information indicating quality of a route indicated by the received route information and storing the obtained quality information in correspondence with a packet destination node and a packet relay node with respect to the wireless terminal in a route information table; a determining step of determining, at every predetermined period, whether a plurality of pieces of route information indicating the same wireless terminal as packet destination node are received based on the route information table; a selecting step of selecting, when it is determined that a plurality of pieces of route information indicating the same wireless terminal as the packet destination node are received, one piece of route information corresponding to a piece of quality information indicating a highest quality among the plurality of pieces of route information; and a relay step of generating a packet including the selected piece of route information and relaying the generated packet to a second wireless terminal (v; z) adjacent to the wireless terminal (x); wherein the selecting, the generating and the relaying are also performed at the predetermined period.