To provide a charging device for a motor-driven vehicle capable of charging a secondary battery by shorted capacity while parking and the like by constituting a function of automatically charging the secondary battery even when a main switch is in an 'off' state.

In a charging device for an motor-driven vehicle 20 provided with a generator 1 and the secondary battery which is charged by the generator 1 while traveling and which supplies power to a driving motor 3, the residual capacity of the secondary battery is detected periodically in the 'off' state of the main switch 5. When the detected residual capacity is equal to or less than a given value, the generator 1 is started to charge the secondary battery 28.