A communication system includes a flow measuring device and a control device. The flow measuring device includes a flow sensor that generates a flow rate signal which is a signal in accordance with a flow rate of intake air drawn into an internal-combustion engine. The flow measuring device transmits the flow rate signal. The control device receives the flow rate signal and performs at least one of injection control of fuel to be supplied to the engine and ignition control at each cylinder of the engine based on the received flow rate signal. The flow measuring device includes a measurement-side transmitting part that transmits various signals by wireless communication, and transmits the flow rate signal by the measurement-side transmitting part. The control device includes a control-side receiving part that receives the various signals by the wireless communication, and receives the flow rate signal by the control-side receiving part.