Abstract: The present disclosure relates to a method for producing a fluorinated organic compound comprises reacting a compound represented by formula (1): (wherein R1 and R2 are each independently a hydrogen atom, a halogen atom, or an organic group, or R1 and R2 optionally form a ring together with the two adjacent carbon atoms; n is 1 or 2; and wherein two R1s are optionally the same or different, two R2s are optionally the same or different, or two R?s or two R2s optionally form a ring together with their adjacent carbon atom), with (A) at least one fluorine source selected from the group consisting of hydrogen fluoride, hydrogen fluoride salts, and fluoride salts, and (B) a halogen source other than fluorine represented by the formula: R3(OX)m (wherein R3 is a hydrogen atom, a cation, or an organic group, X is a halogen atom other than a fluorine atom, and m is an integer corresponding to the valence of R3), to add fluorine and a halogen other than fluorine to the double bond or triple bond.