To provide a technology capable of accurately accumulating communication data without impairing a real-time performance.

A data transmitter 12 intermittently transmits data. A retransmission controller 24 causes the data transmitter 12 to retransmit data which do not normally arrive because of detecting that the data transmitted by the data transmitter 12 did not normally arrive at a receiving side. The retransmission controller 24 schedules, without changing a predetermined transmission schedule of data to be transmitted from the data transmitter 12 according to the transmission schedule, a timing to retransmit the data, which did not normally arrive, during an interval phase between these data.

COPYRIGHT: (C)2011,JPO&INPIT