A process for producing optically active N-tert-butyl-2-piperazinecarboxamide useful as, for example, an intermediate for medicines at a high optical purity by the optical resolution of (R,S)-N-tert-butyl-2-piperazinecarboxyamide with the use of optically active lactic, malic or tartaric acid. The antipode remaining as a useless antipode in the above optical resolution step can be used effectively by racemizing optically active N-tert-butyl-2-piperazinecarboxamide in the presence of a basic compound and effecting optical resolution again.