In a communication system, a control unit and driver units are connected in a daisy chain; each unit includes a corresponding insulated communication circuit, respectively. The control unit measures a communication delay time between the control unit and each driver unit from a response time to transmission of a pulse signal performed to each driver unit during a measurement period. Then, based on each communication delay time, the control unit transmits a shift time to each driver unit for equalizing the timing of signals output by the driver units. When each driver unit receives, from the control unit, an instruction instructing each driver unit to output a signal, each driver unit outputs the signal when the shift time has elapsed.