NOVELTY - A rotatable cylindrical decomposition tank (10) is divided into decompose treatment chamber (3) and air charging chamber (4) through partition walls (6,7). A microorganism supporting carrier and mixture of processed organic waste gas inserted into the treatment chamber are supplied with oxygen through forced ventilation unit.    USE - For decomposition of organic waste collected from the restaurant, residences and food processing factory.    ADVANTAGE - Due to forced ventilation unit gas passage to micro organism supporting carrier and mixture of processed organic waste even during stopped state of the tank, thereby rotation of the decomposition tank is decreased and life of the supporting carrier is extended. Gas passage to microorganism guaranteed by removing harmful surplus water content, thereby anaerobic fermentation is prevented. Since the rotation speed of the tank is low, the phenomenon of gelatinization, lumps formation is suppressed. Due to the rotation and axial movement stirrers, the rotation speed of the tank can be decreased. The apparatus can be used for the manufacture of compost. Growth conditions favorable for aerobic microbe can be maintained. Organic waste is decomposed into water and carbon dioxide in a short time. Provides simple structure.    DETAILED DESCRIPTION - The two partition walls are parallel and provided inside the tank having central rotary shaft. A drain unit ejects the water content from the treatment chamber. A water supply unit supplies water to the treatment chamber. A triangular axial movement stirrer moves the microorganism supporting carrier and processed organic waste. A flat-shaped rotary stirrer (24) is also provided in the treatment chamber. The stirrer is supported on a block placed inside the tank. An insertion unit (30) for organic waste is arranged at the upper portion of the tank. The tank is held at inclined position.    An INDEPENDENT CLAIM is also included for decomposition method of organic waste.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of the organic waste decomposition apparatus.    decompose treatment chamber (3)    air charging chamber (4)    partition walls (6,7)    rotatable cylindrical decomposition tank (10)    feed pipe (11a)    drainage pipe (11b)    warm water pipe (13)    triangle stirrer (21)    flat-shaped stirrer (24)    insertion unit (30)    hopper (31)    motor (32)    spiral conveyor (33)    shaft sealing portion (34)    rest pipe (35)    spiral paddle (36)