To obtain a fluorine-containing copolymer having chemical resistance and electrical characteristics comparable to those of a tetrafluoroethylene- perfluoroalkyl vinyl ether copolymer (PFA) and improved in moldability.

This fluorine-containing copolymer is a copolymer comprising 60-92 mol% of a monomer unit based on CF2CF2 and 8-40 mol% of monomer unit represented by CF2CF(OCH2Rf) (Rf is a halogenated hydrocarbon group) or a fluorine-substituted copolymer in which at least a part of hydrogen atoms in the above copolymer are substituted by fluorine atoms). The fluorine- containing copolymer has ≤1.3 die swell ratio.