A terpene derivative represented by the general formula (I): ##STR1## wherein R.sup.1 represents a lower alkyl group; R.sup.2 represents an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aryl group, an arylalkyl group or a heteroaryl group; n is 0 or 1 or 2; and the symbol " " represents a single or double bond with the proviso that both of the linkages adjacent to each other are not simultaneously single bonds or double bonds which are useful for the preparation of drug, food, perfume and so on, and a process for preparing thereof.