A method of baking both sides of ingredients, the method comprising: putting an upper die over a lower die; and the lower and upper dies (6,7) are different in mass; characterized in heating the lower and upper dies (6, 7) with electric heaters (23, 45) having the same rated power; and wherein the method further comprises: detecting a temperature of a greater mass one of the lower and upper dies (6, 7) to control a consumed power of the electric heater that heats a smaller mass one of the lower and upper dies (6, 7), of which temperature is not detected; and making the temperature of the lower die and that of the upper die closer to each other to bake the ingredients, wherein the greater mass one of the lower and upper dies (6, 7) is heated by the electric heater at the maximum rated consumed power of the electric heater, the consumed power of the electric heater heating the smaller mass one of the lower and upper dies (6, 7) is controlled to get smaller than the maximum rated consumed power based on a temperature information detected about the greater mass one of the lower and upper dies (6, 7), and thereby preventing the die of smaller mass from rising in temperature and making the temperature of the lower die and that of the upper die closer to each other. putting an upper die over a lower die; and the lower and upper dies (6,7) are different in mass; characterized in heating the lower and upper dies (6, 7) with electric heaters (23, 45) having the same rated power; and wherein the method further comprises: detecting a temperature of a greater mass one of the lower and upper dies (6, 7) to control a consumed power of the electric heater that heats a smaller mass one of the lower and upper dies (6, 7), of which temperature is not detected; and making the temperature of the lower die and that of the upper die closer to each other to bake the ingredients, wherein the greater mass one of the lower and upper dies (6, 7) is heated by the electric heater at the maximum rated consumed power of the electric heater, the consumed power of the electric heater heating the smaller mass one of the lower and upper dies (6, 7) is controlled to get smaller than the maximum rated consumed power based on a temperature information detected about the greater mass one of the lower and upper dies (6, 7), and thereby preventing the die of smaller mass from rising in temperature and making the temperature of the lower die and that of the upper die closer to each other. detecting a temperature of a greater mass one of the lower and upper dies (6, 7) to control a consumed power of the electric heater that heats a smaller mass one of the lower and upper dies (6, 7), of which temperature is not detected; and making the temperature of the lower die and that of the upper die closer to each other to bake the ingredients, wherein the greater mass one of the lower and upper dies (6, 7) is heated by the electric heater at the maximum rated consumed power of the electric heater, the consumed power of the electric heater heating the smaller mass one of the lower and upper dies (6, 7) is controlled to get smaller than the maximum rated consumed power based on a temperature information detected about the greater mass one of the lower and upper dies (6, 7), and thereby preventing the die of smaller mass from rising in temperature and making the temperature of the lower die and that of the upper die closer to each other.