NOVELTY - Organic waste (O) is carbonized to produce amorphous carbon (Ar2) in non-supply state of combustion air. Unprocessed gas (Ar1) containing tar and primary combustible gas is circulated to an aggregate of amorphous carbon maintained at ca. 800-1000degreesC under atmospheric pressure. The secondary combustible gas is generated by the contact of tar with the amorphous carbon.    USE - Used for organic waste such as medical waste in a thermal decomposition furnace (claimed) used in an electric power generating system.    ADVANTAGE - The yield of the combustible gas is increased without supplying tar to a steam reforming process. The generation of tar is reduced and the generation of dioxin is prevented.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a thermal decomposition furnace which has a supply tube to supply organic waste to a hollow decomposition tube (12), where a heater heats the organic waste in rotation state of the decomposition tube, an obstacle plate is connected to an inner wall surface of the decomposition tube at a right angle, a communicating hole formed between the obstacle plate and wall surface of the decomposition tube connects the adjacent stopping chambers in a tar decomposition unit, a line segment connecting ends of the decomposition tube and a center shaft is set to theta more than the angle (alpha) between the line segment connecting the rear end of the communicating hole and the center shaft, the tar in the unprocessed gas after producing amorphous carbon is decomposed and the secondary combustible gas is generated by contact of the tar with the amorphous carbon and the secondary combustible gas is removed from the decomposition tube through an extraction opening;    (2) an electric power generating system; and    (3) the production of combustible gas.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of the flow of gas in a thermal decomposition furnace during organic-waste processing. (Drawing includes non-English language text).    decomposition tube (12)    secondary cracking unit (23)    unprocessed gas (Ar1)    amorphous carbon (Ar2)    organic waste (O)