PURPOSE: To prevent position of a bimetal supporting body from shifting and stabilize the operational conditions by fixing each member by an adhesive filled between a case, a fixing metal, and the bimetal supporting body.

CONSTITUTION: A tongue part 6a of a bimetal supporting body 6 is stored and fixed in a heater supporting body 25. The tip of a pin 25a of the supporting body 25 is inserted into a through hole of a case and the lower end 6b of the supporting body 6 is fixed by fastening a fastening screw 28 by the tip of the bimetal 3. After that, an adhesive 26 is filled into an adhesive flow groove 1d of a case 1, the adhesive 26 is led to the groove 1d and the spaces between the through hole 1c of the case 1 and a male screw part 28a of the fastening screw 28 and between the case and the bimetal supporting body 6. By hardening the adhesive 26, those three members; the case 1, the male screw 28a, and the other end 6b of the bimetal supporting body 6 are fixed.