NOVELTY - The apparatus (1) has reactor (2) with liquid phase (22) having filler layer (3) to disassemble sulfur content in biogas and with gaseous-phase (21) on liquid phase. The water supply source (11) supplies water in reactor to set filler layer in immersed state. The top biogas introduction line (L2) introduces biogas from biogas supply source (5) before desulfurization process is made into gaseous-phase, so as to blow off biogas before desulfurization process is made into liquid phase. The lower biogas introduction line (L3) cleans filler layer by aeration flow of blow-in biogas.    USE - Biological desulphurization apparatus of biogas e.g. sewage gas containing organic waste water such as sewage sludge and foodstuff industrial wastewater.    ADVANTAGE - The filler layer can be cleaned effectively without mixing the air. The generation of odor in periphery environment can be prevented. The adsorption degree of the hydrogen sulfide to the filler can be increased, thus improving the desulfurization efficiency. The clogging of filler layer can be eliminated by short-time washing process operation. The cleaning efficiency of the filler layer can be improved greatly. The occurrence of malfunction due to the fall of the methane gas density of heat generation by inflow of oxygen to the dry-type desulfurization can be prevented.    DETAILED DESCRIPTION - The apparatus has biogas supply source that supplies biogas emitted from methane fermentation treatment of organic substance. The cleaning line (L6) is provided from gaseous-phase. The pressure rise blower (8) is provided in cleaning line. The perforated pipe (9) is attached to edge portion of cleaning line, so as to be located in liquid phase more downward than the filler layer. The water supply source is located in the state immersed in the water to the top of the filler layer, so that the top portion of filler layer is sunk into the water. The biogas is introduced into gaseous-phase through top biogas introduction line from the biogas supply source. The biogas is blown off in the water of perforated pipe to the liquid phase through the cleaning line from gaseous-phase by the pressure rise blower. The aeration flow of blow-in biogas is made to clean the filler layer. The water is sprayed by sprinkler structure on the biogas introduced into gaseous-phase. The water sprinkling line (L4,L41) is provided with pump (6) for supplying water to sprinkler structure. The water in liquid phase is sent to the water sprinkling line. The first circulation line (L43) is circulated between the water sprinkling line and the reactor to circulate the water. The second circulation line is branched from water sprinkling line in the downstream of the pump, and is connected to liquid phase more downward than the filler layer. The air charging system is made to introduce air into the second circulation line for making circulating water to dissolve the oxygen. Several filler layers are mutually spaced apart and are arranged in multiple stages in the reactor as filler layer and connected to the mutual space between filler layers. The middle biogas introduction line is made to introduce biogas into mutual space of gaseous-phase. The cleaning line is connected respectively to the gaseous-phase containing the mutual space and the liquid phase containing the filler layer of lowermost stage. The biogas is introduced into mutual space through middle biogas introduction line from the biogas supply source. The biogas is blown off in the water of mutual space through the cleaning line from gaseous-phase by the pressure rise blower. An INDEPENDENT CLAIM is included for cleaning method of biological desulphurization apparatus, involves providing filler layer holding the microorganisms inside the reactor to disassemble sulfur content contained in biogas by microorganisms reaction. The water is supplied to inside of reactor, so that the portion of filler layer is immersed in water. The biogas emitted from methane fermentation treatment of organic substance is introduced into the gaseous-phase in the state in which the liquid phase is hidden in water and the gaseous-phase is not hidden in water. The biogas is allowed to pass through in the filler layer. The sulfur content contained in biogas is adsorbed to the filler of filler layer. The microorganism reaction is maintained at filler separating the sulfur content. The filled layer is cleaned through aeration flow of biogas by introducing the biogas, before desulfurization process is made into the liquid phase.    DESCRIPTION OF DRAWING(S) - The drawing shows a structural block diagram of the biological desulphurization apparatus of biogas. (Drawing includes non-English language text)    Biological desulphurization apparatus (1)    Reactor (2)    Filler layer (3)    Biogas supply source (5)    Pump (6)    Pressure rise blower (8)    Perforated pipe (9)    Water supply source (11)    Gaseous-phase (21)    Liquid phase (22)    Top biogas introduction line (L2)    Lower biogas introduction line (L3)    Water sprinkling lines (L4,L41)    Cleaning line (L6)    First circulation line (L43)