Chitosanase from Bacillus sp. HW-002 was purified with CM-cellulose column chromatography, and HPLC with DEAE- TSK gel and YMC-pack Diol 120. The purified enzyme appeared as a single band on SDS-polyacrylamide gel. The molecular weight of the enzyme was estimated to be about 46 kDa on SDS-polyacrylamide gel, and was estimated to be about 23 kDa by GFC. The optimal pH of chitosanolytic activity was about pH 5.5-6.0, and the purified enzyme was most stable at pH 5.0. The optimal temperature of chitosanolytic activity was $65^{circ}C$ and the enzyme was stable at $45^{circ}C$ for 1 h. Chitosan was the most favorable substrate among various $eta$-glucan. UVmax of the purified enzyme was 195 nmand was not noted around 280 nm. The main product of enzyme reaction with chitosan was chitobiose.