A bacterial strain producing high levels of an extracellular ${eta}$-mannanase and intracellular ${eta}$-mannosidase and ${alpha}$-galactosidase was isolated from soil. The strain isolated was identified as a strain of Sporolactobacillus sp. and designated as Sporolactobacillus sp. M20l. Synthesis of ${eta}$-mannanase by Sporolactobacillus sp. M20l was induced by sucrose, maltose, or locust bean gum. The highest induction rate was obtained with 2% locust bean gum added to the culture medium as a sole carbon source. On the other hand, induction of ${eta}$-mannosidase was observed only with locust bean gum. The optimal media for the enzyme production were established as follows: for ${eta}$-mannanase; 2% locust bean gum, 0.5% peptone, 0.2% KH$_2$PO$_4$, 80 mg/l MgSO$_4$, and 8 mg/l ZnSO$_4$ (pH 6.0), and for ${eta}$-mannosidase; 2% locust bean gum, 0.5% yeast extract, 0.2% KH$_2$PO$_4$, 80 mg/l MgSO$_4$, and 8 mg/l ZnSO$_4$ (pH 5.0). The optimal culture temperatures for production of ${eta}$-mannanase and ${eta}$-mannosidase were found to be 37$^{circ}C$ and 3$0^{circ}C$, respectively. Under the optimal culture conditions, the production of ${eta}$-mannanase and ${eta}$-mannosidase reached the highest levels of 10.6 units/ml and 1.35 units/ml after 30 h and 24 h cultivation, respectively.