PURPOSE: To simply boil rice with assorted ingredients, by a method wherein rice grains, the moisture content of which is regulated to a specified value, a seasoned cooked assorted ingredients, and a seasoning solution are mixidedly charged in a container made of a non-metallic material, and after an opening is sealed with a breathable film, heating is effected.

CONSTITUTION: The moisture content of rice grains 1 is regulated to 13W35%, or after the regulation of the moisture content, a rice grain surface is covered with a high molecular material. Assorted ingredients 2 are heated and seasoned after chipping, or their surfaces are covered with a high molecular material after heating and seasoning. A seasoning solution 3 is 1.1W1.8 times as large as the amount required for increase of the moisture content of the rice grain 1, while the moisture content of which is regulated to 60W65%, or an equivalent quantity of a seasoning solution 3 where a high molecular material, e.g. gelatine, agar-agar, is previously dissolved. A container 4 is made of a material capable of being heated by means of microwave oven, and a breathable film 5 is adhered only to the peripheral edge of the container 4. A film 6 of a material, e.g. an aluminium foil, having high gas barrier properties, is removed before heating. Heating by a microwave oven enables boiling of rice, which has taste feeling, palate, and a shape as in rice hot from an oven, in a short time.