Electric heater for thermal treatment furnace

An electric heater for a heat treating furnace comprising:

• a heating element which is made using a metal wire and installed at an inside surface of a main thermal insulation body;
• an inner thermal insulating material layer and an outer thermal insulating material layer jacketing outside the main thermal insulation body;
• and
• the heating element comprising a plurality of resistance heat emitting portions which are disposed in parallel in the circumferential direction of the main thermal insulation body, wherein:
• a pair of connecting members which are flat in thickness direction of the main thermal insulation body and extend along the circumferential direction of the main thermal insulation body are positioned between a inner thermal insulating material layer and the outer thermal insulating material layer respectively at a distance corresponding to a span between the heat emitting portions;
• and
• ends of each of the resistance heat emitting portions pierce through the main thermal insulation body and the inner thermal insulating material layer, and are connected to a connecting member of corresponding side, respectively.