A battery module charging system comprising: a power transmitting device including a primary coil, the primary coil being configured to transmit AC power; a power receiving unit (70, 8) including a secondary coil, the secondary coil being configured to receive the AC power transmitted from the primary coil by electromagnetic induction, the power receiving unit being configured to convert the received AC power into DC power; and a selection circuitry (21, 25, 29) for use in selectively charging a plurality of cells in a battery module with the DC power, the plurality of cells in the battery module being connected in series to each other, the plurality of cells being secondary batteries; a plurality of charging wirings (17, 18) for use in charging the plurality of respective cells in the battery module, the plurality of charging wiring extending from the selection circuitry; a state monitoring apparatus configured to monitor state signals, each of the state signals indicating a state of one of the plurality of cells in the battery module; a plurality of signal wirings (14,27) extending from the plurality of respective cells in the battery module to the state monitoring apparatus, the state signals being transmitted to the state monitoring apparatus through the plurality of respective signal wirings; and a charging control circuit disposed between the power receiving unit and the selection circuitry, a positioning mechanism (60a, 70a) is configured to allow the power transmitting device to be detachably attached to the power receiving unit, and to position the primary coil and the secondary coil such that the primary coil and the secondary coil are allowed to be electromagnetically coupled to each other when the power transmitting device is attached to the power receiving unit; characterized in that the selection circuitry is configured to select one of the plurality of cells in the battery module and charge the selected cell with the DC power, the charging control circuit is configured to control a start and an end of charging of the one of the plurality of cells in accordance with the state signal, the state signal being monitored by the state monitoring apparatus, the plurality of charging wirings are respectively connected to the selection circuitry and non-end portions of the plurality of signal wirings; and a charging current flowing to each cell flows through a portion of the signal wiring, the portion of the signal wiring extending between the cell and the connected non-end portion of the signal wiring. a power transmitting device including a primary coil, the primary coil being configured to transmit AC power; a power receiving unit (70, 8) including a secondary coil, the secondary coil being configured to receive the AC power transmitted from the primary coil by electromagnetic induction, the power receiving unit being configured to convert the received AC power into DC power; and a selection circuitry (21, 25, 29) for use in selectively charging a plurality of cells in a battery module with the DC power, the plurality of cells in the battery module being connected in series to each other, the plurality of cells being secondary batteries; a plurality of charging wirings (17, 18) for use in charging the plurality of respective cells in the battery module, the plurality of charging wiring extending from the selection circuitry; a state monitoring apparatus configured to monitor state signals, each of the state signals indicating a state of one of the plurality of cells in the battery module; a plurality of signal wirings (14,27) extending from the plurality of respective cells in the battery module to the state monitoring apparatus, the state signals being transmitted to the state monitoring apparatus through the plurality of respective signal wirings; and a charging control circuit disposed between the power receiving unit and the selection circuitry, a positioning mechanism (60a, 70a) is configured to allow the power transmitting device to be detachably attached to the power receiving unit, and to position the primary coil and the secondary coil such that the primary coil and the secondary coil are allowed to be electromagnetically coupled to each other when the power transmitting device is attached to the power receiving unit; characterized in that the selection circuitry is configured to select one of the plurality of cells in the battery module and charge the selected cell with the DC power, the charging control circuit is configured to control a start and an end of charging of the one of the plurality of cells in accordance with the state signal, the state signal being monitored by the state monitoring apparatus, the plurality of charging wirings are respectively connected to the selection circuitry and non-end portions of the plurality of signal wirings; and a charging current flowing to each cell flows through a portion of the signal wiring, the portion of the signal wiring extending between the cell and the connected non-end portion of the signal wiring.