PURPOSE: To provide the heater for heat insulation for cooking capable of directly heating the water filled in a water pan.

CONSTITUTION: This heater has a cylindrical heating element 1 which generates heat when energized. A pair of cap bodies 3, 4 having the diameter larger than the diameter of the heating element 1 are provided at both ends of the heating element 1 and an electric circuit for connecting the heating element 1 to a power source cord 10 is formed within the gap body 4. A thermostat 6 is disposed in this electric circuit by parting the thermostat from the cylindrical heating element 1. The water temp. is sensed by the thermostat 6 through the cap body 4. As a result, the water is directly heated by the heat generation of the heating element 1 simply by immersing the heating element 1 into the water in the water pan. The thermostat 6 disposed apart from the heating element 1 exactly senses the temp. near the actual water temp. through the cap body 4, thereby controlling the on and off of the heating element 1 at the time of ON.OFF controlling of the heating element 1 during heat insulation of the food.