A power assisted bicycle that is drivable by an auxiliary driving force generated by a motor in addition to a human driving force generated by a pedal force from a pedal, comprising: a battery unit having a rechargeable battery, a battery control unit for controlling the charging and discharging of the battery, and a non-CAN, Controller Area Network, terminal; the power assisted bicycle further comprising a motor unit having the motor driven by the battery of the battery unit and a motor control unit, wherein the power assisted bicycle is further comprising an adaptor device that is connected to a non-CAN communication line (61, 62) for communicating a control signal to the battery control unit of the battery unit via the non-CAN terminal and the motor control unit of the motor unit in accordance with a non-CAN standard and a power supply line (63A, 63B) for supplying electric power from the battery to the motor, the adaptor device including a CAN communication circuit configured to process a control signal via a CAN communication line (67A, 67B) from a charging device for charging the battery, and a charging line (64, 65) configured to supply electric power from the charging device to the battery unit, the adaptor device being connectable to a CAN connector for CAN communications, the adaptor device inputting or outputting a control signal required for charging, from or to the adaptor device to or from the charging device and the battery control unit of the battery unit when being connected via the CAN communication line (67A, 67B) to the charging device having the CAN communication line (74A, 74B), the adaptor device inputting or outputting the control signal to or from the charging device via the CAN communication line (67A, 67B) and inputting or outputting the control signal to or from the battery control unit of the battery unit via the non-CAN communication line and the non-CAN terminal, and the battery unit being further connectable to and chargeable by a non-CAN charging device that is connectable via a communication line in accordance with the same standard through the same non-CAN communications as the battery unit. a battery unit having a rechargeable battery, a battery control unit for controlling the charging and discharging of the battery, and a non-CAN, Controller Area Network, terminal; the power assisted bicycle further comprising a motor unit having the motor driven by the battery of the battery unit and a motor control unit, wherein the power assisted bicycle is further comprising an adaptor device that is connected to a non-CAN communication line (61, 62) for communicating a control signal to the battery control unit of the battery unit via the non-CAN terminal and the motor control unit of the motor unit in accordance with a non-CAN standard and a power supply line (63A, 63B) for supplying electric power from the battery to the motor, the adaptor device including a CAN communication circuit configured to process a control signal via a CAN communication line (67A, 67B) from a charging device for charging the battery, and a charging line (64, 65) configured to supply electric power from the charging device to the battery unit, the adaptor device being connectable to a CAN connector for CAN communications, the adaptor device inputting or outputting a control signal required for charging, from or to the adaptor device to or from the charging device and the battery control unit of the battery unit when being connected via the CAN communication line (67A, 67B) to the charging device having the CAN communication line (74A, 74B), the adaptor device inputting or outputting the control signal to or from the charging device via the CAN communication line (67A, 67B) and inputting or outputting the control signal to or from the battery control unit of the battery unit via the non-CAN communication line and the non-CAN terminal, and the battery unit being further connectable to and chargeable by a non-CAN charging device that is connectable via a communication line in accordance with the same standard through the same non-CAN communications as the battery unit.