This study was conducted to investigate the characteristics of hydrogen fermentation with membrane bioreactor (MBR). A continuous stirred tank reactor (CSTR) was also performed at the same operation condition for a comparison. An anaerobic mixed flora obtained by heating anaerobic digested sludge at 80°C for 20 minutes was used as the seed microorganisms. The stable continuous hydrogen fermentation with H2 content of 51% in MBR and H2 content of 58% in CSTR were successfully achieved for 35 days. No methane gas was detected throughout the experiments. The following stiochiometric equation was obtained for the stale hydrogen fermentation from glucose in the MBR: Glucose →0.86H2 + 0.34CO2 + 0.5butyrate + 0.25acetate + 0.19propionate + 0.16lactate + 0.1formate + 0.04succinate + 0.02bacterial cell (C5H9O3N). The hydrogen production rate of MBR was 2.45-2.56l/l/day, which was about 3 times as high as 0.95-0.97l/l/day of CSTR, indicating that the MBR had higher loading capacity. It could be suggested that MBR had a high loading capacity.