Overproduction of intracellular ${eta}$-glucosidase was attempted by modifying the promoter region of a ${eta}$-glucosidase gene cloned from Cellulomonas fimi and expressing it in Bacillus subtilis DB 104. A strong engineered promoter, BJ27UΔ88, was fused to the ${eta}$-glucosidase gene after removing its native promoter. An effective Shine-Dalgamo sequence (genel0 of phage T7) was inserted between the promoter and the ${eta}$-glucosidase structural gene. The modified gene was overexpressed in B. subtilis and produced 1121.5 units of ${eta}$-glucosidase per mg protein which is about $12\%$ of total intracellular protein. Secretion of overproduced intracellular ${eta}$-glucosidase was attempted by using the signal sequence of the Bacillus endoglucanase gene as well as an in-frame hybrid protein of endoglucanase. The hybrid protein was normally secreted into the culture medium and still retained ${eta}$-glucosidase activity.