PURPOSE: To attain smokeless combustion and ensure safety by a method wherein the upper half of a cylinder with inner and outer mesh-construction shells is covered with a sliding cover and heated by a gas burner located below the cylinder and a chaff receiving pan is provided to cover the gas burner from below.

CONSTITUTION: An inner shell 1 and an outer shell 2 are of mesh-construction and a cylinder 3 with the inner and outer shells 1 and 2 is heated by a gas burner 6 from below and rotated. Therefor, a hot air flow zone A in the same direction as the rotating direction is developed inside a gap 5 between the inner and outer shells 1 and 2, and smoke 17 in the inner drum generated from material to be burned is introduced into the hot air flow zone A through a mesh 4 and re-burned to smoke-less gas. A sliding cover 11 surrounding the upper half of the cylinder 3 is gradually slid to adjust the smoke generation, and the final control of roasting degree takes place. A chaff receiving pan 12 is located below the burner 6, and the accumulation of chaff prevents the burner 6 from being influenced by wind and provides a heat-insulating effect as well.