To provide a method for preparing both enantiomers of karanone which are contained in aromatic woods such as aloeswood and agilawood and are useful as a perfume material of a perfuming composition for fragrant cosmetics, foods, drinks, and the like.

The method for preparing the optically active karanone comprises mixing a mixture containing (+)-karanone and/or (-)-karanone with an optically active tartaric acid derivative to form a clathrate compound of an optically active isomer of karanone with the optically active tartaric acid derivative and subsequently separating the optically active isomer of karanone from the clathrate compound. The method permits acquisition of the both enantiomers of the optically active karanone, which is heretofore hard to obtain, by a simple operation in a high yield and yet at a high chemical and optical purity. The optically active tartaric acid derivative used is readily available and can be almost quantitatively recovered and repeatedly used thereby permitting reduction of the preparation cost. The both enantiomers of karanone obtained have excellent properties different from each other from the view point of perfume chemistry and therefore are supplied as a promising fragrant substance for perfuming fragrant cosmetics, foods, drinks, and the like.