Battery charger for an electric vehicle

The present invention relates to an on-board charger (OBC) for charging a battery of an electric vehicle. A battery charging device for electric vehicle according to an embodiment of the present invention comprises: a rectifying circuit for rectifying alternating current power to direct current power; a power-factor correction (PFC) unit with a buck and boost circuit for stepping up or down the voltage of the direct current power based on an inputted first control signal; and a DC-DC converter unit for converting the voltage of the stepped up or down direct current power into a predetermined charging voltage value based on an inputted second control signal and supplying the direct current power converted into the predetermined charging voltage value to a battery.