NOVELTY - A biomass processing system has hydrogen fermenter (2), hydrogen-fermentation gas recovery unit (31), methane-fermentation tank (5), methane-fermentation gas recovery unit (61), solid-liquid separator, and gasifier (13). The fermenter carries out hydrogen fermentation of biomass (1), and methane-fermentation tank carries out methane fermentation of hydrogen-fermentation residue (4). The dehydrated residue (9) is gasified.    USE - For processing biomass (claimed), such as organic waste, resource crops, waste from foodstuffs industries, paper manufacturing industries and stock raising industries, sludge of organic waste, excrement, and city sewage, and producing combustible gas useful as fuel for electric-power generation.    ADVANTAGE - The processing system enables effective usage of biomass, without composting, and effective usage of anaerobic fermentation residue. Since the generation amount of methane gas per unit time is increased, the energy time yield from biomass is also increased. The dry energy required for gasification is reduced. The heat energy is recovered, and the amount of waste material is decreased. Since the methane-fermentation residue is alkaline, the amount of alkali used for biomass processing is reduced. The processing system is compact.    DETAILED DESCRIPTION - A biomass processing system has a hydrogen fermenter (2), a hydrogen-fermentation gas recovery unit (31) connected to the hydrogen fermenter, a methane-fermentation tank (5), a methane-fermentation gas recovery unit (61) connected with the methane-fermentation tank, a solid-liquid separator, and a gasifier (13). The fermenter carries out hydrogen fermentation of biomass (1), and the hydrogen-fermentation gas recovery unit recovers the hydrogen-fermentation gas (3). The methane-fermentation tank receives the hydrogen-fermentation residue (4) and carries out methane fermentation, and the methane-fermentation gas recovery unit recovers the methane-fermentation gas (6). The solid-liquid separator separates the methane-fermentation residue (7) and collects dehydrated residue (9) which is gasified into a combustible gas (14) by the gasifier.    An INDEPENDENT CLAIM is included for processing method of biomass, which involves carrying out hydrogen fermentation of biomass to obtain hydrogen-fermentation gas and hydrogen-fermentation residue, carrying out methane fermentation of hydrogen-fermentation residue to obtain methane-fermentation gas and methane-fermentation residue, solid-liquid separating the methane-fermentation residue to obtain dehydrated filtrate (10) and dehydrate residue, and gasifying the dehydrated residue.    DESCRIPTION OF DRAWING(S) - The figure shows the systematic diagram explaining the biomass processing method.    biomass (1)    hydrogen fermenter (2)    hydrogen-fermentation gas (3)    hydrogen-fermentation residue (4)    methane-fermentation tank (5)    methane-fermentation gas (6)    methane-fermentation residue (7)    dehydrated residue (9)    dehydrated filtrate (10)    gasifier (13)    combustible gas (14)    hydrogen-fermentation gas recovery unit (31)    methane-fermentation gas recovery unit (61)