NOVELTY - A biological desulfurization apparatus has absorption tower in which biogas containing hydrogen sulfide is contacted with circulating water, such that circulating water absorbs hydrogen sulfide and made into absorption liquid, bio-reaction unit in which oxidative degradation of hydrogen sulfide in absorption liquid is performed, such that absorption liquid is made into process liquid, circular flow path which supplies process liquid to tower, a temperature control unit which heats process liquid and a pH control tank in which pH of heated process liquid is controlled.    USE - Apparatus is used for biological desulfurization method (claimed) of hydrogen sulfide in biogas produced by methane fermentation tank.    ADVANTAGE - The apparatus is economical and highly efficient, and biological desulfurization method using the apparatus is performed with reduced alkali consumption.    DETAILED DESCRIPTION - A biological desulfurization apparatus has an absorption tower (1) in which biogas containing hydrogen sulfide is contacted with pH-controlled circulating water, such that the circulating water absorbs hydrogen sulfide in biogas and made into absorption liquid, a bio-reaction unit (2) in which oxidative degradation of hydrogen sulfide in absorption liquid is performed aerobically by microorganism, such that the absorption liquid is made into a process liquid, a circular flow path (11) which supplies the process liquid as circulating water to the absorption tower, a temperature control unit (3) which heats the process liquid to-be-supplied to circular flow path and a pH control tank in which the pH of heated process liquid is controlled. An INDEPENDENT CLAIM is included for biological desulfurization method.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of biological desulfurization apparatus. (Drawing includes non-English language text)    Absorption tower (1)    Bio-reaction unit (2)    Temperature control unit (3)    Pump (10)    Circular flow path (11)