A fryer includes a potential generator; and an oil tub installed with a discharging electrode of the potential generator. The potential generator includes a transformer that is composed of a primary coil and a secondary coil; a feedback control circuit that feeds back one terminal of the secondary coil to one terminal of the primary coil to adjust a voltage of the secondary coil; an output control portion that is provided on the other terminal of the secondary coil to impart a predetermined low frequency vibration to an output of the secondary coil which causes the discharging electrode physically vibrates; and the discharging electrode that is formed of a conductive material and provided on the other terminal of the secondary coil via the output control portion. A vibration frequency of the low frequency vibration applied is 40 Hz to 60 Hz which is determined by the output control portion.