The present invention relates to a method for producing a fluorocopolymer which comprises a polymerization reaction of a fluorine-containing ethylenic monomer with a fluorovinyl ether derivative represented by the following general formula (I): CF.sub.2.dbd.CF--O--[CF.sub.2CF(CF.sub.3)O].sub.n--(CF.sub.2).sub.m-A (I) (wherein n represents an integer of 0 to 3, m represents an integer of 1 to 5, and A represents --SO.sub.2X or --COOY; X represents a halogen atom or --NR.sup.1R.sup.2; R.sup.1 and R.sup.2 are the same or different and each represents a hydrogen atom, an alkali metal, an alkyl group or a sulfonyl-containing group and Y represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) to give a fluorocopolymer,said fluorine-containing ethylenic monomer being a perhaloethylenic monomer represented by the following general formula (II): CF.sub.2.dbd.CF--R.sub.f.sup.1 (II) (wherein R.sub.f.sup.1 represents a fluorine atom, a chlorine atom, R.sub.f.sup.2 or OR.sub.f.sup.2; R.sub.f.sup.2 represents a straight or branched perfluoroalkyl group having 1 to 9 carbon atoms, which may have an ether oxygen atom(s)) and/or a hydrogen-containing fluoroethylenic monomer represented by the following general formula (III): CHX.sup.1.dbd.CFX.sup.2 (III) (wherein X.sup.1 represents a hydrogen atom or a fluorine atom and X.sup.2 represents a hydrogen atom, a fluorine atom, a chlorine atom, R.sub.f.sup.3 or OR.sub.f.sup.3; R.sub.f.sup.3 represents a straight or branched perfluoroalkyl group having 1 to 9 carbon atoms, which may have an ether oxygen atom(s)), and said polymerization reaction being carried out in a saturated perfluorohydrocarbon while additional feeding of the fluorine-containing ethylenic monomer and fluorovinyl ether derivative being carried out.