PURPOSE: To stabilize the quality and improve the durability as well as the reliability of the heating body by a method wherein two kinds of wires are piled for predetermined lengthes under linear conditions and are welded, thereafter, the heating body is formed by winding them into a spiral shape.

CONSTITUTION: When a heating body is manufactured in a condition that first and second heating bodies 5, 6, which are arranged in a sheath 1 with a desired gap between the spiral sections, are connected, two kinds of wires, forming the heating bodies 5, 6, are piled for a predetermined length under linear conditions and are welded, thereafter, respective wires are wound into spiral shape to form the heating body. According to this method, forming and working properties may be improved remarkably, the quality thereof is stabilized and the durability as well as the reliability of operation of the heating body may be improved.