Abstract: An electric heater with a low electromagnetic wave effect, the heater is mainly used to generate heat in a main pipe line, and is provided with a loop line and an electric heating line laid juxtaposed and parallel with each other with a suitable distance therebetween; by serially connecting the ends respectively of the loop line and the electric heating line as well as coupling the other ends respectively of the loop line and the electric heating line with the electric current loop of an electric source, when electric current flows through the loop line and the electric heating line, the current flows therethrough in a contrary direction to offset most of electromagnetic waves; in this way, the electromagnetic wave effect of the electric heater is effectively lowered.