To achieve a preparation for cooking simply in a short time in a combustor for cooking an object to be grilled such as meat by housing a fire retarding charcoal on a bottom part of a container while the fire retarding charcoal is heated by a heating source arranged on the same bottom part of the container to eliminate time and labor for starting a fire

In cooking using a combustor 1, firstly, a fire retarding charcoal 3 is heated up to about 500°C by a heating source 4 and infrared rays are radiated from the fire retarding charcoal 3. The infrared rays with the wavelength there of 2-5 micron radiated the most is absorbed by material without passing through the material. So, the infrared rays are taken into a material 5 to be cooked to harden the surface tissue thereof. Hence, a defense film is formed to keep liquid taste components (inosinic acid, glutamic acid or the like) generated in the material 5 to be cooked from be spilled. This enables the obtaining of a tasty cooked food with the taste components confined therein while the internal temperature of the material to be cooked can be raised quickly to about 70°C with a large heating effect.