Membrane membrane-reinforcement-member assembly, membrane catalyst-layer assembly, membrane electrode assembly and polymer electrolyte fuel cell

A membrane membrane-reinforcement-member assembly comprising:

• a polymer electrolyte membrane that is substantially quadrilateral in shape and has a first main surface and a second main surface;
• a pair of first membranous membrane reinforcement members that respectively extend along one opposed pair of sides of four sides of said polymer electrolyte membrane and are embedded in said polymer electrolyte membrane such that their main surfaces are unexposed;
• and
• a pair of second membranous membrane reinforcement members that respectively extend along the other opposed pair of sides of four sides of said polymer electrolyte membrane and are embedded in said polymer electrolyte membrane such that their main surfaces are unexposed;
• wherein said pair of first membrane reinforcement members and said pair of second membrane reinforcement members are arranged such that said pair of first membrane reinforcement members are positioned closer to the first main surface than said pair of second membrane reinforcement members, and are so embedded as to overlap each other in four corners of said polymer electrolyte membrane, when viewed in a thickness direction of said polymer electrolyte membrane.