Enhancement of enzymatic saccharification of lignified stalks of Kudzu ( Pueraria lobata) was examined. The yield of enzymatically hydrolyzed glucose obtained from alkaline pretreated ligneous kudzu stalks with 1.0% NaOH solution at 373 K for 1 h was 48% of cellulose included. The enhancement of amount of obtained glucose from the alkaline pretreated kudzu stalks was examined using silicon under visible light irradiation at room temperature. Hydrogen evolved continuously during irradiation. The quantity of obtained glucose increased up to ca. 1.5 times large value after the treatment with silicon for 2 h, and the yield of glucose was 70% after enzymatic saccharification for 72 h.