PURPOSE: To balance heat distribution and to prevent variation in heating of a food, by a method wherein a pitch at a central part between holes formed in a distribution plate located between a heating device and a food is made different from those at both ends.

CONSTITUTION: A distribution plate 9 is placed between a gas burner 5 at the upper part of the rear surface of a heating chamber 1 and a food 4. e.g., fishes. A pitch between red-heat regulating holes 11 formed in the central part of the distribution plate 9 is made different from those at both end parts, and a pitch (a) between the red-heat regulating holes 11 at the central part is made larger than a pitch (b) between the red-heat regulating holes 11 at both end parts. Since heat capacity at the both end parts is lower than that at the central part, it is heated to deep-redness, and strong infrared rays are radiated to the end part of the food 4. Since the central part has a higher heat capacity, it is not heated to deep-redness, and since weak infrared rays are radiated to the central part of the food 4, heat distribution is well-balanced, and this enables prevention of variation is heating of the food.