NOVELTY - A biological desulfurizing apparatus has a biogas inflow line for flowing in biogas (0a) from edge portion of a biological desulfurization tower (1), a filled layer (1a) consisting of filler to which microorganisms is adhered provided in biological desulfurization tower, a process-gas outflow line (7) for being another edge portion of biological desulfurization tower, and which discharges process gas (0c) in back stage of filled layer, a circulation gas line (8), a control mechanism (9), a calculator (11), and a signal transmission mechanism (12).    USE - Apparatus is used for biological desulfurizing of biogas (claimed).    ADVANTAGE - The biological desulfurizing apparatus economically and efficiently treats high-load hydrogen sulfide and converts the treated hydrogen sulfide to sulfuric acid and eliminates in-device blockage by precipitation of sulfur, without cleaning process.    DETAILED DESCRIPTION - A biological desulfurizing apparatus has a biogas inflow line for flowing in biogas from edge portion of a biological desulfurization tower, a filled layer consisting of filler to which microorganisms is adhered provided in biological desulfurization tower, a process-gas outflow line for being another edge portion of biological desulfurization tower, and which discharges process gas in back stage of filled layer, a circulation gas line for circulating through portion of process gas at edge portion at which biogas of biological desulfurization tower flows in, a hydrogen-sulfide densitometer (3) and a gas meter (4) provided in biogas inflow line, a control mechanism which controls amount of circulating gas provided in circulation gas line, a calculator for computing hydrogen-sulfide load amount from hydrogen-sulfide concentration level of biogas by hydrogen-sulfide densitometer and gas flow rate value by gas meter and a signal transmission mechanism of circulating gas in which the control mechanism of amount of circulating gas is operated with respect to calculation result of hydrogen-sulfide load amount of calculator. The biological desulfurizing apparatus in which circulation liquid (0d) is water-sprinkled in a biological desulfurization tower, and hydrogen sulfide is biologically removed from biogas and methane-fermented organic waste, and is emitted. An INDEPENDENT CLAIM is included for biological desulfurization method of biogas.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the biological desulfurizing apparatus. (Drawing includes non-English language text)    Biogas (0a)    Process gas (0c)    Circulation liquid (0d)    Biological desulfurization tower (1)    Filled layer (1a)    Hydrogen-sulfide densitometer (3)    Gas meter (4)    Process-gas outflow line (7)    Circulation gas line (8)    Control mechanism (9)    Calculator (11)    Signal transmission mechanism (12)