The present invention provides a novel gene encoding a protein having an excellent catalyst ability for producing (S)-N-substituted cyclic imino acid represented by the general formula (2) (=the (S)-cyclic imino acid (2)): and to provide a novel method for producing the (S)-cyclic imino acid (2) by an asymmetric hydrolization of the N-substituted cyclic imino acid ester represented by the general formula (1): in a manner of gene engineering technology utilizing the novel gene provided.