Fluoroalkyl derivatives which are novel compounds represented by the following general formula (I) or (II) of: ##STR1## orR.sub.1 --CH.dbd.CR.sub.2 (CF.sub.2).sub.n F (II)(wherein R.sub.1 stands for ##STR2## (where X stands for a hydrogen atom, a chlorine atom, a bromine atom, a fluorine atom, an iodine atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group or a nitro group), an aroyloxy group, or an alkyl or alkoxycarbonyl group having 1 to 20 carbon atoms, and R.sub.2 stands for a hydrogen atom or a methyl group; and n stands for an integer of from 1 to 20.) A process for the preparation of the derivative is a process comprising reacting an olefin compound and a fluoroalkanesulfonyl chloride in the presence of a metal catalyst, or a process comprising an additional alkali treatment step which follows the aforementioned process.