The utility model provides an anti-creeping and anti-medium-seepage electric heater. The anti-creeping and anti-medium-seepage electric heater comprises an electric heating element shell I, an electric heating element shell II, a heat conduction insulating layer I, a heat conduction insulating layer II, a heating wire, a grounding wire I, a grounding wire II, a residual current transformer, an equipment flange and sealing members. The shells are internally filled up with magnesium powder, and the external layer of the heating wire is provided with two metal shells; the portion between the electric heating element shell I and the heating wire is filled up with a heat conduction insulating layer, and a tube opening is provided with one sealing member; the portion between the electric heating element shell II and the electric heating element shell I is filled up with a heat conduction insulating layer, and tube openings are provided with the sealing members; the grounding wire I is connected with the electric heating element shell I; and the grounding wire II is connected with the equipment flange.