The present invention provides a process for producing an optically active allene represented by formula (1): ##STR00001## wherein R.sup.2 and R.sup.3 are different and each represents a hydrogen atom, an optionally substituted C.sub.1-20 alkyl group or an optionally substituted C.sub.6-20 aryl group, and R.sup.4 represents an acyl group, which comprises reacting an allene derivative represented by formula (2): ##STR00002## wherein R.sup.1 represents a hydrogen atom or an optionally substituted acyl group and R.sup.2 and R.sup.3 have the same meaning as defined above, with an acylating agent having an acyl group represented by R.sup.4 when both R.sup.1s are each a hydrogen atom or with water when both R.sup.1s are each an acyl group represented by R.sup.4, in the presence of an enzyme catalyst. According to this production process, an optically active allene can be produced efficiently and enantioselectively from an allene derivative having a symmetrical structure.