To prevent the generation of uncomfortable sound associated with water boiling in a warming mode by providing a first heating means heating liquid inside a pot and the second heating means executing heating and warming of the liquid and reducing a power to the second heating means so as to execute energizing when the temp. of the liquid is below warming temp. at the time of the warming mode.

When a power change-over switch 19 is at a high power side at the time of heating water by a boiling mode, a first relay contact 15b is operated so as to operate the first heating means 16 and the second relay contact 17b is operated so as to energize the second heating means 18. When the power change-over switch 19 is at a low power side, the first relay contact 15b is operated so as to energize the first heating means 15. Then, after boiling, it is checked whether temp. is more than the warming one by the warming mode which is shifted after energizing to the heating means 16 and 18 are stopped, energizing to the second heating means 18 is stopped when temp. is more than the warming one and the second heating means 18 is energized with a resistor 20b when it is less than the warming one.