A charger includes a choke coil and a choke iron core disposed on a plane surface of heat dissipating fins. Furthermore, a face plate, a control circuit board, a drive circuit board, the heat dissipating fins, a fan and a ventilation plate are separately series-connected in alignment and fitted on a base thereof. The electric power from a power supply input is transmitted to the drive circuit board through an input terminal, whereupon alternating current passes through a rectifier circuit and is converted into direct current thereat. Upon charging, results from a detector are transmitted to a microprocessor, which effectuates switch over to an output circuit through transistors, while diodes prevent current reflux. The electric power is then transmitted to a battery by means of a transformer coupled to an electric power terminal and further passing through one more rectifier circuit and a wave filter circuit.