Electric resistance water heating apparatus

The utility model relates to a water resistance heating heater with compact structure, small occupied space, lower fabrication cost, high thermal efficiency, no pollution, safe and reliable working, convenient regulation and control, and easy popularization. A return pipe connector is arranged on the side wall of a plastic pipe casing, an insulation supporting seat with the middle part provided with a through hole and the bottom part provided with an annular dummy club is inserted on the bottom opening of the plastic pipe casing, a sealing gasket is positioned between the annular dummy club of the insulation supporting seat and the bottom surface of the insulation supporting seat, the bottom part of the plastic pipe casing is connected with a compact insulation covering with the open-ended bottom surface through a thread, two electrodes are respectively arranged in the plastic pipe casing, the electrodes are respectively led out the through hole on the insulation supporting seat and an opening on the bottom surface of the compact insulation covering, an inner sealing gasket is sleeved on the electrodes and at the position which corresponds to an installation hole on the insulation supporting seat, the leading-out ends of the electrodes are also mutually connected with a power line with a plug, and an insulating protective sleeve is sleeved at the leading-out parts of the electrodes.