NOVELTY - A fermenter produces methane gas from soy sauce lees. A sealing-type tank is equipped with a lower fermenter (1) and an upper gas-holding chamber (2). The soy sauce lees is diluted with a digestive liquor and slurried with activated sludge-containing aqueous liquids in the fermenter. A gas discharge pipe (8) ejects gas from the gas-holding chamber, after completion of methane fermentation.    USE - Methane fermentation of soy sauce lees to generate biogas.    ADVANTAGE - The need for desalination is eliminated, simplifying the methane fermentation apparatus. The fermenter enables efficient generation of biogas, by sufficient processing of the soy sauce lees. The decomposed product of the lees can be used as compost and fertilizer for cultivation of vegetables and garden plants.    DETAILED DESCRIPTION - A fermenter produces methane gas from soy sauce lees. A sealing-type tank is equipped with a lower fermenter (1) and an upper gas-holding chamber (2). The soy sauce lees is diluted with a digestive liquor and slurried with activated sludge-containing aqueous liquids in the fermenter. A gas discharge pipe (8) ejects gas from the gas-holding chamber, after completion of methane fermentation. A heating unit (3) heats the substance in the fermenter to a preset temperature, during stirring of the slurry in an airtight state using a stirring apparatus (4). A pipe (11) connects the inside of the digestive liquor storage tank (7) and the fermenter. A desulfurizing apparatus (13) and the gas-holding chamber are connected with the airtight gas discharge pipe. A solid liquid separation machine (14) is connected to the storage tank and a filtrate tank (12).    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of the methane fermentation apparatus.    fermenter (1)    upper gas holding chamber (2)    heating unit (3)    stirring apparatus (4)    digestive liquor storage tank (7)    gas discharge pipe (8)    pipe (11)    filtrate tank (12)    desulfurizing apparatus (13)    solid-liquid separation machine (14)