PURPOSE: To cook a delicious rice by setting a boiling period to about 20 minutes irrespective of a rice-cooking quantity through obtaining the intensity of fire during the boiling period by fuzzy inference on the basis of the detected temperature of an inner pot and rice-cooking quantity and through opening and closing a plurality of control valves for adjusting fire.

CONSTITUTION: An initial temperature detected by a thermistor is inputted to an arithmetic circuit 9 and first fuzzy inference part 8. The arithmetic circuit 9 obtains the average of temperature rise rates at several points of an inner pot and inputs it to the first fuzzy inference part 8. The first fuzzy inference part 8 fuzzy-infers a rice-cooking quantity by membership function and fuzzy rule and inputs the quantity to a second fuzzy inference part 11. The second fuzzy inference part 11 performs fuzzy inference from the temperature of the thermistor and the rice-cooking quantity, outputs a control output corresponding to fire during a boiling period to a controller 12, and controls opening and closing of a plurality of gas burners for adjusting fire. Thus, a delicious rice is cooked in about 20 minutes' boiling time irrespective of the rice-cooking quantity.