To provide an electrolyte material for polymer electrolyte fuel cells having a high softening temperature and being excellent in durability, and an electrolyte membrane and a process for producing a membrane-electrode assembly using it. An electrolyte material made of a polymer containing a segment A of a polymer containing repeating units based on a perfluoromonomer having an ion exchange group and having a polymerizable double bond, at least one of carbon atoms in the polymerizable double bond being a carbon atom contained in an alicyclic structure, and a segment B of a fluoropolymer containing substantially no ion exchange group, and an electrolyte membrane and a membrane-electrode assembly using it.