PURPOSE: To obtain the finishing of the food with a high accuracy by a method wherein a sensor voltage, detected after additional heating is applied to the food, and the saturated voltage of the senser obtained by an experiment are compared to decide the finishing of the food and whereby the heating time for the food is corrected.

CONSTITUTION: The finishing of the food is controlled by means of the sensor such as a gas sensor, a humidity sensor or the like by detecting the sensity or the humidity of gas produced by heating the food. In the method of control, a first heating time, in which the output voltage of the sensor is moved from an initial value upon starting of the heating of the food to a set voltage preset at an area wherein the output of the sensor is varied suddenly, is obtained, and the additional heating is effected by the second heating time obtained by multiplying said first heating time by a constant preset in accordance with the weight of the food to be heated. Subsequently, the third heating time is decided by a decision to which range of standard the output of the sensor after the additional heating is belonging, and then the repeated additional heating is effected. The range of standard is decided by the saturated voltage of the output of the sensor upon finishing of the heating which is determined by the weight of the food.