A network system that includes a plurality of nodes that include a wireless communication function and that carries out data communication via the nodes, each of the nodes comprising: a data controller for setting and correcting an entrywise link value of each of evaluation target entries stored in an information parameter table which establishes and stores therein a correspondence between the evaluation target entries that affect a communication quality of the node and the entrywise link values that are parameters of the communication quality of each of the evaluation target entries; a local link value-calculating unit for calculating a local link value based on the entrywise link value of each of the evaluation target entry that is stored in said information parameter table, the local link value indicating a value corresponding to communication quality of the node; a frame processor for transceiving a communication frame to carry out processes related to the communication frame, the communication frame including a destination address field, a source address field, a first total link value field, a threshold value field that is set by the source communication node of the communication frame, and data field which includes data of the communication path that is used to transfer the communication frame till the communication node that is the destination of the frame, the first total link value being a value corresponding to a quality of a communication path that is used to transfer the communication frame until said frame is received by said frame processor; a total link value-calculating unit for calculating, based on the first total link value, a radio wave strength between a node transferring the data and the node receiving the data, and said local link value, a second total link value that indicates a quality of a communication path that is used to transfer the data, the total link value-calculating unit outputting the second total link value to the frame processor; a path determining unit for comparing the second total link value calculated by the total link value-calculating unit and the threshold value included in the communication frame, and for determining to transfer the data to a destination node when the second total link value is not smaller than the threshold value, and for determining not to transfer the data to the destination node when the second total link value is smaller than the threshold value, wherein the frame processor, when it is determined to transfer the data to a destination node, is adapted to update the total link value field of the communication frame with the second total link value calculated by the total link value-calculating unit in the communication frame, and to transfer the communication frame to the destination node. a data controller for setting and correcting an entrywise link value of each of evaluation target entries stored in an information parameter table which establishes and stores therein a correspondence between the evaluation target entries that affect a communication quality of the node and the entrywise link values that are parameters of the communication quality of each of the evaluation target entries; a local link value-calculating unit for calculating a local link value based on the entrywise link value of each of the evaluation target entry that is stored in said information parameter table, the local link value indicating a value corresponding to communication quality of the node; a frame processor for transceiving a communication frame to carry out processes related to the communication frame, the communication frame including a destination address field, a source address field, a first total link value field, a threshold value field that is set by the source communication node of the communication frame, and data field which includes data of the communication path that is used to transfer the communication frame till the communication node that is the destination of the frame, the first total link value being a value corresponding to a quality of a communication path that is used to transfer the communication frame until said frame is received by said frame processor; a total link value-calculating unit for calculating, based on the first total link value, a radio wave strength between a node transferring the data and the node receiving the data, and said local link value, a second total link value that indicates a quality of a communication path that is used to transfer the data, the total link value-calculating unit outputting the second total link value to the frame processor; a path determining unit for comparing the second total link value calculated by the total link value-calculating unit and the threshold value included in the communication frame, and for determining to transfer the data to a destination node when the second total link value is not smaller than the threshold value, and for determining not to transfer the data to the destination node when the second total link value is smaller than the threshold value, wherein the frame processor, when it is determined to transfer the data to a destination node, is adapted to update the total link value field of the communication frame with the second total link value calculated by the total link value-calculating unit in the communication frame, and to transfer the communication frame to the destination node.