A charging system for charging a power storage device mounted on a vehicle by a power supply provided outside said vehicle, said charging system comprising: a charging unit configured to be able to charge said power storage device by an electric power supplied from said power supply when said vehicle is in a rest state and comprising an inlet provided in said vehicle to be able to be connected to a cable for transferring the electric power from said power supply to said vehicle, and a charger provided in said vehicle; and a charging control unit configured to control said charging unit, said charging control unit including a charging execution unit configured to operate said charging unit in order to charge said power storage device, a detection unit configured to detect a change in position of said vehicle, a charging stopping unit configured to cause said charging unit to stop a charging of said power storage device, when said detection unit detects the change in position of said vehicle from a starting position of the charging of said power storage device while said charging unit charges said power storage device, a diagnostic unit configured to diagnose a state of said charging unit associated with a supply of the electric power, when said charging stopping unit stops the charging of said power storage device, a determination unit configured to determine whether an operation of said charging unit is able to be resumed, based on a diagnostic result of said diagnostic unit, and a charging resuming unit configured to cause said charging unit to resume the charging of said power storage device, when said determination unit determines that the operation of said charging unit is able to be resumed; wherein said charger is configured to supply the electric power fed into said inlet to said power storage device under the control of said charging execution unit and said charging resuming unit while stopping the supply of the electric power to said power storage device under the control of said charging stopping unit, and said diagnostic unit is configured to diagnose the state of said charging unit by detecting at least a connection state of said cable and said inlet. a charging unit configured to be able to charge said power storage device by an electric power supplied from said power supply when said vehicle is in a rest state and comprising an inlet provided in said vehicle to be able to be connected to a cable for transferring the electric power from said power supply to said vehicle, and a charger provided in said vehicle; and a charging control unit configured to control said charging unit, said charging control unit including a charging execution unit configured to operate said charging unit in order to charge said power storage device, a detection unit configured to detect a change in position of said vehicle, a charging stopping unit configured to cause said charging unit to stop a charging of said power storage device, when said detection unit detects the change in position of said vehicle from a starting position of the charging of said power storage device while said charging unit charges said power storage device, a diagnostic unit configured to diagnose a state of said charging unit associated with a supply of the electric power, when said charging stopping unit stops the charging of said power storage device, a determination unit configured to determine whether an operation of said charging unit is able to be resumed, based on a diagnostic result of said diagnostic unit, and a charging resuming unit configured to cause said charging unit to resume the charging of said power storage device, when said determination unit determines that the operation of said charging unit is able to be resumed; wherein said charger is configured to supply the electric power fed into said inlet to said power storage device under the control of said charging execution unit and said charging resuming unit while stopping the supply of the electric power to said power storage device under the control of said charging stopping unit, and said diagnostic unit is configured to diagnose the state of said charging unit by detecting at least a connection state of said cable and said inlet.