Abstract: A device for purifying fuel is safe and can be easily controlled, and is of low cost by applying a low frequency, low voltage and low current signal to fuel during the supply thereof. The device comprises a fuel supply pipe interposed between a fuel tank and an engine, a fuel communication pipe interposed in the fuel supply pipe, a conductive coil wound around a periphery of the fuel communication pipe, a protective cover for covering the conductive coil, and an AC signal generator connected to a battery and the conductive coil for generating a low frequency, low voltage and low current signal to the conductive coil.