To solve two defects of drying of boiled rice and yellowing and odor of boiled rice at a stroke by not only warming the interior of a kettle, but also moistening it to keep tasty boiled rice warm.

A moistening tank is set in a kettle or the like, thereby adding an effect of preventing deterioration of boiled rice during warming of boiled rice, such as yellowing of boiled rice, odor attended on such yellowing, drying of boiled rice and deterioration of gloss on the surface thereof attended on the drying, and deterioration of taste during warming of a conventional rice cooker equipped with a warming function, by adding not only warming, but also a moistening function to give a sterilizing function.