Sasa borealis leaf has been known to have anti-diabetic properties. In this study, we tried to evaluate the effects of Sasa borealis leaf extract (SBE) on the inhibition of $alpha$-glucosidase activity and postprandial glycemic response following ingestion of four carbohydrate-rich foods; cooked rice, ramen (instant noodle), noodle, and bread. Fourteen healthy female adults consumed 50 g of glucose (control) or one of the four foods containing 50 g of available carbohydrate with or without 2,000 mg of SBE. The activity of $alpha$-glucosidase was inhibited dose-dependently by SBE. With SBE, blood glucose concentration at 15 min and the positive area under the curve (AUC) of postprandial glycemic response at 15 min and 30 min after consuming each of the four foods were reduced significantly. As the result, total positive AUC during 120 min was decreased in case of taking cooked rice or bread. Glycemic index and glycemic load of the four foods were declined from 13% to 23% with SBE. The results of this study suggest that SBE may be effective for postprandial glucose control by inhibiting $alpha$-glucosidase activity.