PURPOSE: An organic waste composting apparatus and a method thereof are provided to minimize the moisture content of organic waste and to maximize the degradability of organic waste by maximizing the activation of aerobic microorganisms and improving the structure of an air diffuser. CONSTITUTION: A composting apparatus of organic waste comprises an input hopper(100), a crusher, a crushed material reservoir(110), a sending tool, a fermenter(140), an agitation tank(150), an aging tank(160), a compost reservoir(170), a selection and packaging tub(180), a leachate reservoir(200), an aeration tank(210), a solid-liquid separation tank(220), and a water treatment tank(230). The crusher comprises a first crusher(102) and a second crusher(104). The sending tool comprises first, second, and third conveyors(112,114,116). A magnetron(120) is installed on the top of the first conveyor. The magnetron irradiates a microwave to maintain the moisture content of the crushed material at 50-65%. A magnetic separator(130) is installed on the top of the second conveyor. A fermentation liquid fertilizer sprayer is installed on the top of the third conveyor. A seed compost conveyor(118) is horizontally installed with a gap between the third conveyer and the seed compost conveyor. A chaff layer with a fixed thickness is formed on the upper part of an air pipe installed on the bottom of the fermenter. [Reference numerals] (120) Magnetron； (130) Magnetic separator； (140) Fermenter； (150) Agitation tank； (160) Aging tank； (170) Compost reservoir； (180) Selection and packaging tub； (200) Leachate reservoir； (210) Aeration tank； (220) Solid-liquid separation tank； (230) Water treatment tank； (300) Sawdust storage tank； (AA) Composting treatment process； (BB) Leachate treatment process본 발명은 유기성 폐기물 퇴비화 장치 및 방법에 관한 것으로, 투입호퍼, 투입호퍼로 투입된 유기성 폐기물을 파쇄하는 파쇄기, 파쇄물을 저장하는 파쇄물 저장조, 저장된 파쇄물을 인출 반송하면서 호기성 미생물을 포함한 발효 액비가 뿌려지도록 유도하는 반송수단, 반송된 파쇄물과 종자퇴비를 혼합저장하면서 발효 액비가 뿌려져 1차 발효시키는 발효조, 1차 발효된 혼합물을 교반하면서 발효 액
