A communication system in which communication is performed between a vehicle and a power supply device by performing superposition and separation of a communication signal on and from a control line for transmitting a control signal used for control of charging of an object to be charged and a reference potential line connected to a reference potential, the communication signal being different from the control signal, the superposition and separation being performed by a superposition/separation unit, the object to be charged being connected to a power supply line (31, 32), wherein the vehicle comprises a power storage device that is the object to be charged, a first charging control device connected, via first two extended lines in the vehicle, to one end of each of the control line and the reference potential line, the first charging control device being configured to control charging in accordance with the control signal; a connector for connecting the one end of the control line to one of the first two extended lines and for connecting the one end of the reference potential line to another of the first two extended lines, and a first communication device connected, via a first superposition/separation unit to each of first two branch lines (36a, 36b) branched from each of the first two extended lines, the first communication device being configured to perform communication by the communication signal, and wherein the power supply device comprises a second charging control device connected, via second two extended lines in the power supply device, to another end of each of the control line and the reference potential line, the second charging control device being configured to control charging in accordance with the control signal, and a second communication device connected, via a second superposition/separation unit, to each of second two branch lines (35a, 35b) branched from each of the second two extended lines, the second communication device being configured to perform communication by the communication signal, characterized in that the vehicle comprises a first common mode choke coil serially connected to each of the first two extended lines between the first charging control device and branch portions (36a1, 36b1) of the first two branch lines (36a, 36b1), and a second common mode choke coil serially connected to each of two internal lines connected to each of the control line and the reference potential line in the connector, the second common mode choke coil being provided in the connector, and the power supply device comprises a third common mode choke coil serially connected to each of the second two extended lines between the second charging control device and branch portions (35a1, 35b1) of the second two branch lines (35a, 35b). a power storage device that is the object to be charged, a first charging control device connected, via first two extended lines in the vehicle, to one end of each of the control line and the reference potential line, the first charging control device being configured to control charging in accordance with the control signal; a connector for connecting the one end of the control line to one of the first two extended lines and for connecting the one end of the reference potential line to another of the first two extended lines, and a first communication device connected, via a first superposition/separation unit to each of first two branch lines (36a, 36b) branched from each of the first two extended lines, the first communication device being configured to perform communication by the communication signal, and a second charging control device connected, via second two extended lines in the power supply device, to another end of each of the control line and the reference potential line, the second charging control device being configured to control charging in accordance with the control signal, and a second communication device connected, via a second superposition/separation unit, to each of second two branch lines (35a, 35b) branched from each of the second two extended lines, the second communication device being configured to perform communication by the communication signal, a first common mode choke coil serially connected to each of the first two extended lines between the first charging control device and branch portions (36a1, 36b1) of the first two branch lines (36a, 36b1), and a second common mode choke coil serially connected to each of two internal lines connected to each of the control line and the reference potential line in the connector, the second common mode choke coil being provided in the connector, and a third common mode choke coil serially connected to each of the second two extended lines between the second charging control device and branch portions (35a1, 35b1) of the second two branch lines (35a, 35b).