This study investigated the effects of soy bean extract fermented by Bacillus subtilis MORI (BTD-1) on blood glucose, hemoglobin A1c (HbA1c), plasma insulin, and pancreatic ${eta}$ islets in db/db mice. The BTD-1 (500 mg/kg) group showed significantly lower fasting blood glucose level (p<0.01) and postprandial 2 h blood glucose level (p<0.01) compared with the db control group. The BTD-1 (500 mg/kg) group showed significantly lower HbA1c level compared with the db control group (p<0.01). After 8 weeks of BTD-1 administration, the pancreatic islet architecture was preserved and the immunofluorescent intensities of insulin in BTD-1 (500mg/kg) group apparently increased compared to in the db control group. Plasma insulin levels were found to be significantly higher in the BTD-1 (500 mg/kg) group than in the db control group (p<0.05). In summary, our results suggest that BTD-1 has an anti-diabetes effect in a non-insulin dependent diabetes mellitus mouse model.