A wireless relay device for relaying packets via a wireless network (N1), comprising: a wireless communicator configured to receive a plurality of first packets transmitted from a plurality of wireless devices in the wireless network (N1) and under the wireless relay device ; an aggregator configured to aggregate a plurality of sets of data that are respectively included in the plurality of first packets to generate a second packet when the plurality of first packets received by the wireless communicator are addressed to the wireless relay device ; and a transfer controller configured to transfer the second packet to a transfer destination, wherein a size of a header (H) of the plurality of first packets is larger than a size of a payload (PL) of the plurality of first packets, the aggregator is configured to aggregate a plurality of sets of time data, each of which is included in the header (H) of each of the plurality of first packets, a plurality of sets of identification data (F4), each of which identifies each of the plurality of wireless devices and is included in the header (H), and a plurality of sets of payload data, each of which is included in the payload (PL) of each of the plurality of first packets, to generate the second packet, and the aggregator is configured to incorporate reference time data (F3) indicating a reference time into the second packet, and to aggregate the plurality of sets of time data, each of which is included in the header (H) of each of the plurality of first packets, as a plurality of sets of offset data, each of which indicates a deviation time with respect to the reference time. a wireless communicator configured to receive a plurality of first packets transmitted from a plurality of wireless devices in the wireless network (N1) and under the wireless relay device ; an aggregator configured to aggregate a plurality of sets of data that are respectively included in the plurality of first packets to generate a second packet when the plurality of first packets received by the wireless communicator are addressed to the wireless relay device ; and a transfer controller configured to transfer the second packet to a transfer destination, wherein a size of a header (H) of the plurality of first packets is larger than a size of a payload (PL) of the plurality of first packets, the aggregator is configured to aggregate a plurality of sets of time data, each of which is included in the header (H) of each of the plurality of first packets, a plurality of sets of identification data (F4), each of which identifies each of the plurality of wireless devices and is included in the header (H), and a plurality of sets of payload data, each of which is included in the payload (PL) of each of the plurality of first packets, to generate the second packet, and the aggregator is configured to incorporate reference time data (F3) indicating a reference time into the second packet, and to aggregate the plurality of sets of time data, each of which is included in the header (H) of each of the plurality of first packets, as a plurality of sets of offset data, each of which indicates a deviation time with respect to the reference time. <EOS>