Japanese Patent Laying-Open No. 2000-354332 discloses a charging device for an electric vehicle. This charging device includes a relay for opening and closing an electric power supply path from an external electric power source to an electric vehicle; a leakage detecting circuit for detecting electrical leakage based on current flowing through the electric power supply path; a test circuit for intentionally causing electrical leakage at the start of supplying electric power from the external electric power source to an electric power supply circuit; a control circuit for controlling the relay so that the electric power supply path is brought into an open state, when the leakage detecting circuit detects electrical leakage. Prior to charging, the control circuit checks an operation of the leakage detecting circuit.
In the charging device disclosed in Japanese Patent Laying-Open No. 2000-354332, the control device turns on the relay to check the operation of the leakage detecting circuit. However, if the relay has a welded contact, the control circuit cannot cause the electric power supply path to be interrupted after the checking of the operation of the leakage detecting circuit. In this case, the electrical leakage is likely to remain. It is considered that this makes it impossible to perform a charging operation smoothly using the foregoing charging device. Japanese Patent Laying-Open No. 2000-354332 does not disclose an operation of the control circuit when the welding of the relay occurs.