TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - The apparatus has fermentation tank (1) which is provided horizontally and rotatably. A raw material injection hopper (2) and an opening for raw material injection (5a), are formed on one end portion of the tank (1). Similarly, a residue emission duct (3) and an opening for fermented residue emission (6a) are provided on the other end portion of tank (1). Ventilating fan (10) and jet pipe (9), are provided to ventilate inside the tank. Rotation axis (15) and stirring blade (16) are also included in the tank to stir the processed substance. Requisite amount of chaff, rice straw, straw or withering grass is added as fermentation auxiliary to mixture of organic waste and ground material of microbial bed, provided in the fermentation tank. The fermented residue is ejected through residue outlet (3).    TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The residual plant fiber texture in the decomposition microbial bed is ground, mashed and pressed by a screw-type grinding apparatus, so that the water content of the microbial bed is increased.The amount of ground material of microbial bed is 3-30 weight parts (wt.pts), preferably 5-10 wt.pts, for 100 wt.pts of organic waste. The amount of fermentation auxiliary is 30 wt.pts or less, preferably 5-10 wt.pts, based on 100 wt.pts of organic waste. The processed substance mixture is stirred intermittently. The ratio of intermittent stirring period and leaving period is 1:10-1:180. The mixture is inserted into the fermentation tank by using the ventilating fan. An openable cover material (24) is arranged by the side of the raw material injection hopper (2). A housing (4) is provided on the residue emission duct (3) which is protruded to the opening (6a) externally. An inlet port (7) formed on the top of the duct (3) connects inner side of the tank and housing through emission duct. An exhaust port (8) is formed on the top of the hopper (2) connects jet pipe and inner side of the tank through the injection hopper. A deodorant (11) is provided near the jet pipe. The stirring blade has rotation axis (15) arranged inside the fermentation tank.