To prevent anomaly (theft or fall off of connectors) of a charging cable occurring due to thefts or mischiefs during charging of an electric vehicle.

When charging a battery 1 for an electric vehicle, an onboard battery 4 and a commercial power supply 21 are connected together with a charging cable 22, equipped with connectors 23 and 24 at both ends. A connecting state of a connector 24 on a motor vehicle side is detected by a limit switch 15. When the security for theft prevention is operated by a theft preventing ECU 7 (operation prohibiting state, detection means), the limit switch 15 operates and the fall off of the connector 24 is detected, and then a buzzer 20 is operated and an alarm is issued. By doing this, the anomaly of the charging cable 22 due to thefts or mischiefs can be prevented.