Activated carbon fiber(ACF) which was used as catalytic oxidant in this study was used to remove hydrogen sulfide(H₂S). H₂S was removed effectively under the condition of 80 weight% of ACF`s moisture content, 200 ppm H₂S in inlet concentration, and 100h^(-1) of its space velocity(flow rate/packed volume, load = 11.01 g-H₂S-S/dry-fiber, day). It took 45 days to remove H₂S completely. Although drastic decrease of the removal ratio was found at pH value less than 0.5 in drain water due to the accumulated sulfuric acid(H₂SO₄) resulting from the oxidation of H₂S in the wet ACF, oxidizing ability was recovered by washing out H₂SO₄ in the fiber. A single supply of methyl mercaptan(CH₃SH) resulted in the production of dimethyl disulfide(CH₃SSCH₃), and methyl mercaptan was perfectly oxidized to methane sulfonic acid(CH₃SO₃H) in the mixed supply with H₂S. Dimethyl sulfide(CH₃SCH₃) was not removed even at half inlet sulfur load of CH₃SH.