PURPOSE: To disable the release of interlock without removing a charging cable.

CONSTITUTION: A vehicle-carried charger charges a vehicle-carried battery by connecting a charging cable of external power supply to a charging plug receptacle 5 of a charger 2 accommodated in a charging box 3 providing a cover 3b which can be opened or closed freely. An interlock switch 6 for detecting opening or closing condition of the cover 3b is provided near the cover 3b and this interlock switch 6 is connected to a key switch circuit. Thereby, when the cover 3b is closed, the interlock is released. As a result, a vehicle cannot start to run, if the charging cable is not removed and the cover 3b is not closed after the charging, thereby preventing the damage of the charging cable.