A perfluoro compound containing a group of the general formula: ##STR1## wherein X stands for a fluorine atom, perfluoro-alkoxy groups, or --OM where M stands for an alkali metal ion or an alkaline earth earth ion and having connected to the aforementioned group a perfluoro-alkyl group possessing a total of 2 to 6 carbon atoms in the trunk carbon chain thereof is subjected to a temperature in the range of 100.degree. to 500.degree. C. to produce a perfluoro-(N-vinylamine) compound now containing the aforementioned group as converted into the formula:>NCF.dbd.CF.sub.2