A bacterium which utilizes ${varepsilon}$-caprolactam as a sole source of carbon and nitrogen was isolated from sludge of Shinchun river in Taegu and identified as Arthrobacter globiformis N-2-l. The growth medium for the optimum culture condition was composed of 0.4% ${varepsilon}$-caprolactam, 0.02% $K_2HPO_4$, 0.05% $KH_2PO_4$, 0.02% $MgSO_4{cdot}7H_2O$, 0.01% $FeCl_3{cdot}6H_2O$ and 0.05% yeast extract. The optimum pH and temperature for growth were 7.0 and $30^{circ}C$ respectively. The bacterial growth on the ${varepsilon}$-caprolactam medium did not require any other organic nitrogen source such as yeast extract, although it was remarkably stimulated by the yeast extract. The bacteria utilized wide range of sugars and organic acids such as ${alpha}$-ketoglutarate, adipate and P-hydroxybenzoate. The bacteria could use all kind of amino acids, ${varepsilon}$-Caprolactam in the medium was consumed completely in the timecourse culture at $30^{circ}C$ for 60 hr on the shaker by the bacteria. Decomposition product of ${varepsilon}$-caprolactam by Arthrobacter globiformis N-2-1 was ${varepsilon}$-aminocaproic acid.