Extracellular cyclodextrin glucanotransferase (CGTase) from Paenibacillus sp. JK-12 was purified through sev-eral purification steps consisting of ammonium sulfate precipitation and chromatographies on DEAE-sephadex A-50 and Mono QIM HR5/5. The purified CGTase exhibited a single band on SDS-PAGE and was estimated to be approximately 82 kDa. The isoelectric point of the enzyme was 7.2 as determined by isoelectric focusing. The CGTase from Paenibacillus sp. JK-12 had a transglucosylation activity at the C-2 position of L-ascorbic acid. The optimum pH and temperature for the CGTase activity were 8.0 and 5$0^{circ}C$, respectively. The enzyme activity was stable from pH 6.0 to 9.() and at temperatures up to 55$^{circ}C$ at pB 8.0, having 80% residual activity. The activity of the CGTase was strongly resistant to metals such as A $g^{+}$ and $Ba^{2+}$ but slightly inhibited by H $g^{+}$, N $i^{2+}$ and $Mg^{2+}$. The enzymeproduced $alpha$ -cyclodextrin ($alpha$-CD) and $eta$-CD as the main products from starch, but not ${gamma}$-CD.X>-CD.