NOVELTY - Solid anaerobic fermentation composting device (9) comprises (a) a solid anaerobic fermentation part (1) for composting organic waste of low molecular-weight compound type, (b) a pre-processing unit (3) for converting organic waste inside a first fermentation tank to low molecular-weight compounds by hydrolysis and acid fermentation, and for supplying low molecular-weight compounds converted by substitution reaction inside substitution tank to the solid anaerobic fermentation part, and (c) a post-processing unit (4) for aging or supplying a portion of fermented compost to an aging tank.    USE - Used as solid anaerobic fermentation composting device.    ADVANTAGE - The device promotes methane fermentation, produces high quality compost, can be installed underground at different regions, and is environmentally friendly.    DETAILED DESCRIPTION - Solid anaerobic fermentation composting device (9) comprises (a) a solid anaerobic fermentation part (1) for composting organic waste of low molecular-weight compound type pretreated in absence of oxygen overlapped with a cover on open upper portion of an underground anaerobic fermenter tank by stirring with an agitating unit (2), and for collecting biogas generated during methane fermentation via a collecting part installed on empty space between the roof and the ceiling, (b) a pre-processing unit (3) for converting organic waste inside a first fermentation tank to low molecular-weight compounds by hydrolysis and acid fermentation for several hours to several days, and for supplying low molecular-weight compounds converted in anaerobic condition by substitution reaction inside substitution tank to the solid anaerobic fermentation part, installed with the underground anaerobic fermenter tank, and (c) a post-processing unit (4) for aging or supplying a portion of fermented compost to an aging tank connected to the underground anaerobic fermenter tank. The pre-processing unit is separated with the solid anaerobic fermentation part via automatically raising first partition wall. The post-processing unit is separated with the solid anaerobic fermentation part via a fixed partition wall installed with a conveying screw. The pre-processing unit and the post-processing unit draws produced compost or supplies organic waste by forming a gate on upper portion of the first fermentation vessel and the aging tank.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of the solid anaerobic fermentation composting device.    Solid anaerobic fermentation part (1)    Agitating unit (2)    Pre-processing unit (3)    Post-processing unit (4)    Solid anaerobic fermentation composting device (5)