To efficiently obtain an optically active alcohol of high purity that is useful as an intermediate for medicines and agrochemicals in a high yield by reacting a reductase with a specific alkyl vinyl sulfide to form an optically active dialkyl sulfide, followed by desulfurization of the product.

A reductase originating from a microorganism, for example, a yeast or the like is reacted with an alkyl vinyl sulfide represented by formula I [R1 is a (substituted) aryl; R2 is a (substituted) 1-6C alkyl] for example, 2- phenyl-3-methylthio-2-propene-1-al to for, an optically active dialkyl sulfide represented by formula II (* indicates an asymmetric carbon atom having either the R configuration or the S configuration). Then, the resultant dialkyl sulfide product is subjected to desulfurization reaction to prepare the objective optically active alcohol represented by formula III. During the reactions, the amount of the reductase is preferably in the range of 0.1-30%(w/v).