Disclosed is a fluororesin-coated polymer film for reinforcing polymer electrolyte membranes, which is obtained by forming, on at least one side of a polymer film, a coating of a reaction product of a fluorine-containing copolymer (A), which contains a fluoroolefin, a cyclohexyl group-containing acrylate and a hydroxyl group-containing vinyl ether as constitutional components, and a crosslinking agent (B) having two or more isocyanate groups. The fluororesin-coated polymer film exhibits sufficiently high initial adhesion strength to polymer electrolyte membranes, and maintains sufficiently high adhesion strength when in use.