Novel intermediates for the production of aminoacetyl pyrrolidine carbonitrile derivatives ensure the safe and efficient production of the compounds. Specifically, the present invention provides a sulfonyloxyacetyl pyrrolidine derivative, represented by the following formula:(Chemical Formula 1) (wherein R1 is a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C3-C6 cycloalkyl group, a substituted or unsubstituted arylmethyl group, a substituted or unsubstituted aromatic hydrocarbon, a substituted or unsubstituted aromatic heterocyclic ring or a substituted or unsubstituted aliphatic heterocyclic ring; R2 is CONH2 or CN; and X is CH2, CHF or CF2.)