NOVELTY - The stirrer (100) has an impeller (12) equipped in one side of circumferential surface of rotary shaft (11). A rotating blade (12a) actively mixes the organic waste colliding with the leading end of the rotating blade. The rotating blade is formed with the angle of 120-160 degrees . The mixing protrusion (13) is equipped in both sides of rotating blade and formed with angle of 10-30 degrees with respect to rotational direction of impeller. The mixing protrusion is inclined around the lateral portion at an angle of 30-60 degrees with respect to rotating blade.    USE - Stirrer of fermentation device for fermentation of food waste, domestic animal carcass and liquid manure.    ADVANTAGE - The inner temperature of the fermentation device is maintained, the steam is made to easily disappear and the environmental contamination is minimized. The fermentation rate is increased, and the fermentation time is reduced. The organic waste colliding with the leading end of the impeller is induced, and the organic waste is actively mixed. The leachate generation is prevented. The blockage of the air spray hole entrance due to the debris of the air spray hole entrance in the fermentation mixing is prevented.    DETAILED DESCRIPTION - The stirrer has rotary shaft equipped at the center of inside of the fermenting device, to transfer the rotation power and to mix the organic waste. The organic waste is pushed to the outside with the centrifugal force of the rotating blade of the impeller. Multiple rotating blades are formed symmetrical to the rotary shaft impeller. A mixing board (14) is formed with an impeller air spray hole (15). A bad smell removing apparatus (20) is provided to remove smell generated by the organic waste in the natural fermentation. The heat insulator is provided to maintain temperature of the inside of fermenting device. Multiple bottom surface air spray holes are formed in the bottom surface of the fermenting device. The fermentation product of 20-60 weight% is formed by primary fermentation and secondary fermentation.    DESCRIPTION OF DRAWING(S) - The drawing shows a front perspective view of the stirrer of fermentation device.    Rotary shaft (11)    Impeller (12)    Rotating blade (12a)    Mixing protrusion (13)    Mixing board (14)    Impeller air spray hole (15)    Bad smell removing apparatus (20)    Stirrer (100)