A bacteria identified as Bacillus brevis has been isolated from the soil. It has been found to secrete cellulase extracellularly whose production increased almost five times on addition of galactose in the culture medium. Production of cellulase has been found optimal at pH 5.5, 37 degrees C and 175 rpm speed using environmental orbital shaker. The cellulase has been purified using ultrafiltration and Sephadex G-200 column chromatography. The native molecular weight of the enzyme is found to be 33,000 +/- 2000 using Sephadex G-200 gel filtration chromatography. The subunit molecular weight (33,000 +/- 2,000) indicate monomeric nature of the enzyme. The enzyme showed Michaelis Menten kinetics exhibiting Km approximately 1.7 +/- 0.1 mg/ml for CMC. The enzyme activity got inhibited by heavy metals viz. Hg+2 and Ag+2.