This study was aimed to obtain a microbial consortium capable of fermenting cellulosic biomass at 60°C and producing hydrogen gas. We obtained the microbial consortium C-2 from compost samples by the culture experiment using ball-milled cellulose (BMC) as a carbon source-containing medium. For the hydrogen gas production, the optimum cultivation condition of the microbial consortium was obtained from the result of the experiment using 3-L jar fermenters: pH 7.2, agitation speed of 200 rpm, and temperature of 60°C. The amount of hydrogen gas production was 1.37 mol-H2/mol-hexose under the optimal condition. The analysis of organic acids in the hydrogen fermentation under the optimal condition suggested that hydrogen gas was produced by the microbial consotium mainly via acetic acid. Clostridium stercorarium was found to dominate at 55.2% in the microbial consortium from the result of 16S rDNA clone libraries analysis. It was concluded that the microbial consortium C-2 is capable of fermenting cellulosic biomass at 60°C and producing stable hydrogen gas.