A differential communication circuit is connected to a communication line formed of a positive communication line and a negative communication line for differential communication. The differential communication circuit includes: a series circuit that includes a resistor element and a connection switch. The resistor element is connected between the positive and negative communication lines when the connection switch is turned on. The circuit also includes a transmission unit that is configured to output a differential signal to the communication line and a controller that is configured to change impedance of the communication line by turning on the connection switch in a period during which the transmission unit does not output the differential signal.