| 摘要 |
The present invention is to provide an immersion heater capable of completely avoiding a situation where an outer circumference border of a spiral heating element is pressed to an inner wall of a protecting tube, and preventing disconnection due to contact between adjacent portions of the heating element. In the immersion heater of the invention, a metal heating element 8 is strip, and one edge portion of this strip heating element 8 is inserted into, and held in the spiral groove 7 to form a spiral heating part 9. Cylindrical-body supporting members 11 that each have a diameter smaller than an inner diameter of the ceramic bottom protecting tube 2 and larger than an outer diameter of the spiral heating part 9 and are fitted into a hollow portion of the insulating cylindrical body 6 are arranged in openings at a fore-end and a back-end of the insulating cylindrical body 6, respectively.
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