To provide an enzymatic resolution process for efficiently producing an optically active N-protected-octahydro-1H-indole-2-carboxylic acid denoted by the formula (2): ##STR00001## by using an enzyme capable of asymmetrically hydrolyzing the --CO.sub.2R.sup.1 group in the formula (1) ##STR00002## wherein R.sup.1 indicates an alkyl group having a carbon number of 1 to 4, R.sup.2 indicates a protecting group of the imino group, and the carbon atoms marked with asterisks (*) indicate asymmetrical carbon atoms.