To provide a communication system capable of selecting a communication pathway of shortest communication time, when there are multiple communication pathways.SOLUTION: In a communication system where a first communication device and a second communication device can be connected by multiple communication pathways, the first communication device includes an address information transmission section transmitting address information each of the multiple communication pathways to the second communication device, a selection section for selecting a communication pathway of shortest communication time, on the basis of the communication time each of the multiple communication pathways, a message information transmission section for transmitting the message information to the second communication device by the communication pathway selected by the selection section, and a reception section for receiving the response information to the message information from the second communication device. The second communication device includes an address information receiving section for receiving address information from the first communication device, a message information receiving section for receiving message information from the first communication device, and a transmission section for transmitting the response information to the message information to the first communication device.SELECTED DRAWING: Figure 4
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