The present invention provides a process for producing a fluorinated fluorosulfonylalkyl vinyl ether represented by general formula (2):

CF₂CFO(CF₂CF(CF₃)O)_nCF₂CF₂SO₂F  (2)

wherein n is an integer from 0 to 10, comprising fluorinating a perfluorovinylether sulfonate with SF₄ and HF, the perfluorovinylether sulfonate being represented by general formula (1):

CF₂CFO(CF₂CF(CF₃)O)_nCF₂CF₂SO₃M  (1)

wherein M is Ma or Mb_1/2, provided that Ma is an alkali metal and Mb is an alkaline earth metal; and n is as defined above. According to the process of the invention, the fluorinated fluorosulfonylalkyl vinyl ether can be produced in high yield in an industrially advantageous manner.