An object of the present invention is to provide a polymer electrolyte membrane meeting power generation properties and physical durability at the same time and having high durability. A polymer electrolyte membrane comprising a microporous membrane and a fluorine-based polymer electrolyte contained in a pore of the microporous membrane, wherein pore distribution of the microporous membrane has a pore distribution with a center of distribution in a pore diameter range of 0.3 μm to 5.0 μm, and the fluorine-based polymer electrolyte composition contains a fluorine-based polymer electrolyte (component A) having an ion exchange capacity of 0.5 to 3.0 meq/g.