The detritiation system using the hydrogen-oxidizing microorganism isolated from the sandy loam soil was developed, which is designed to remove HT in a gas phase. Silicone hollow-fiber-membrane tubes was used to separate gas phase and liquid phase in which microorganisms are cultured. HT in the gas phase diffuses through the tube membrane to the liquid phase, oxidized to HTO and retained in the liquid phase. Detritiation system showed rapid and complete removal of HT mixed in the room air of atmospheric H2 concentration.