[Abstract] Chemolithoautotrophic bacteria are the bacteria that grow without utilizing organic matters as substrate and photosynthesis. They acquire energy for cell growth by oxidizing inorganic compounds and assimilate CO_2 to synthesis cell components and other organic compounds. They have important role of CO2 fixation and primary producer, matter cycle environmental clean-up in nature, and are used for waste treatment. Manufacture of useful substances from CO_2 using chemolithoautotriphic bacteria is also expected. Among the chemolitoautotrophic bacteria, this article focuses on usefulness, handling and basal culture method of hydrogen-oxidizing bacteria under autotrophic condition.