The first to fourth generation processes described above are executed by the second pulse generator 125, and thereby the wireless receiver 12 can perform timing synchronization with the wireless transmitter 11.

In the embodiment, it is assumed that, when the control instruction signal is output, the second controller 127 that receives the control instruction signal controls the control target device 3 without a delay. A timing at which the second controller 127 controls the control target device 3 may be delayed from the timing at which the control instruction signal is received. The delay time in this case (that is, the time from when the second controller 127 receives the control instruction signal until the second controller actually controls the control target device 3) is a delay time caused by the hardware and can be considered as being almost constant. In this case, since the one control cycle includes the above third time, the above fourth time, and the above delay time, the first to fourth generation processes described above can be executed by replacing the count value Ct corresponding to the one control cycle, with a count value Ct' obtained by subtracting the delay time from the count value Ct. Since the count value Ct' is approximate to the count value Ct, the count value Ct' may be referred to as the count value corresponding to one control cycle.