NOVELTY - Anaerobically treating organic pollutant material comprises using a sulfuric-acid reduction microbe.    USE - For anaerobic treatment of organic pollutant material contained in wastewater.    ADVANTAGE - The anaerobic treatment of organic pollutant material is steadily carried out with high efficiency.    DETAILED DESCRIPTION - An organic pollutant material is anaerobically treated in presence of sulfuric-acid reduction microbe. The concentration and/or sulfuric-acid reduction activity of the sulfuric-acid reduction microbe is monitored. The service condition is controlled to maintain the sulfuric-acid reduction microbe concentration in a predetermined range, based on the monitored value. Thus, an anaerobic-treatment method of organic pollutant material is enabled.    An INDEPENDENT CLAIM is included for anaerobic treatment apparatus of organic pollutant material, comprising an organic pollutant material storage tank (1), pre-processing tank (2), anaerobic reaction tank (3), chemical solution tank (4), piping, and units (A-E). The organic pollutant material is introduced to the storage tank. The pre-processing tank performs pre-processing, which promotes the souring of organic material by adding a sulfate. The organic pollutant material processed by the pre-processing tank is fed to the anaerobic reaction tank, and anaerobic treatment is carried out. A sulfate solution is stored in the chemical solution tank. The piping supplies the sulfate solution to a storage tank and/or pre-processing tank. Units (A,C) measure micro concentration and/or sulfate ion concentration in sludge, in the pre-processing tank and anaerobic reaction tank, respectively. Unit (B) adjusts the amount of sulfate solution supplied to the storage tank, pre-processing tank and/or anaerobic reaction tank, based on the microbe concentration and/or sulfate ion concentration value. Unit (D) adjusts the amount of sulfate supplied to anaerobic reaction tank, based on the microbe concentration and/or sulfate ion concentration value, hydrogen concentration and acetic acid concentration.    DESCRIPTION OF DRAWING(S) - The figure shows a conceptual diagram illustrating the structure of an anaerobic treatment apparatus of an organic pollutant material. (Drawing includes non-English language text).    natural water storage tank (1)    pre-processing tank (2)    anaerobic reaction tank (3)    chemical-solution tank (4)    digestive gas holder (5)