The NCS inhibited the activity of glucosyltransferase which was produced by Streptococcus mutans JC-2, and the rate of inhibition at $100muM<$ and $200muM$ were 74.0% and 99.8%, respectively. It was stable in alkali condition, but unstable in acid condition. It was also stable up to $80^{circ}C$. The kinetic study of the inhibition by NCS was carried out by Lineweaver-Burk plot and Dixon plot. It was non-competitive inhibition, determined by the two plots and $K_i$ and $K_i$ values were $15muM$ and $19.3muM$ respectively. The NCS did not show cytotoxicity against human gingival cells at $K_i$ ($15muM$, $150muM$, $1,500mu$ M) concentrations. It had less cytotoxicity than chlohexidin, which has usually been used as the agent of anticaries. To evaluate the industrial applicability of the NCS, human pluck tooth was used. The inhibitory rates of tooth calcification and calcium ion elution by the NCS were 41 % and 2.5 times, respectively. These results suggested that NCS from Bacillus sp. S-1013 is an efficient anticaries agent.