NOVELTY - An electrode structure (S1) comprises: a pair of electrode catalyst layers (1) containing carbon particles supporting platinum particles as a catalyst and a polymer electrolyte membrane (2) sandwiched between the layers, where the membrane is made of a sulfonated polyarylene-based polymer (A1). The polymer (A1) is a copolymer; and has an ion exchange capacity of 1.7-2.3 meq/g; and the polymer contains a component insoluble in N-methylpyrrolidone, in an amount of less than or equal to70%, after the polymer is subjected to heat treatment under a constant temperature atmosphere of 120degreesC for 200 hours.    USE - For a polymer electrolyte fuel cell useful in electrical apparatus and transport apparatus (claimed) (e.g. vehicle, ship such as submarine, personal computer and cellular phone).    ADVANTAGE - The polymer electrolyte fuel cell has a excellent power generation performance and excellent durability to the heat during the operation of a fuel cell; and has a excellent dimensional stability.    DETAILED DESCRIPTION - An electrode structure (S1) for a polymer electrolyte fuel cell comprises: a pair of electrode catalyst layers (1) containing carbon particles supporting platinum particles as a catalyst and a polymer electrolyte membrane (2) sandwiched between the electrode catalyst layers, where the polymer electrolyte membrane is made of a sulfonated polyarylene-based polymer (A1). The sulfonated polyarylene-based polymer (A1) is a copolymer of formula (II); and has an ion exchange capacity of 1.7-2.3 meq/g; and the polymer contains a component insoluble in N-methylpyrrolidone in an amount of less than or equal to70% relative to the total amount of the polymer, after the polymer is subjected to heat treatment for exposing the same under a constant temperature atmosphere of 120degreesC for 200 hours.    l, m and n=not defined.    INDEPENDENT CLAIMS are included for the following:    (1) manufacturing the electrode structure (S1) involving: forming the polymer electrolyte membrane from a solution of sulfonated polyarylene-based polymer (A1); coating a catalyst paste containing catalyst particles in which platinum particles are supported on carbon particles and a polymer electrolyte on a sheet-like support and drying the same to form an electrode catalyst layer; and thermally transferring to join the electrode catalyst layer to both sides of the polymer electrolyte membrane containing a solvent of less than or equal to 0.5 wt.% by weight of the total membrane;    (2) a polymer electrolyte fuel cell comprising the electrode structure (S1); and    (3) an electrical apparatus or a transport apparatus comprising the polymer electrolyte fuel cell.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of the electrode structure for polymer electrolyte fuel cell.    electrode catalyst layer (1)    polymer electrolyte membrane (2)    diffusion layer (3)    carbon paper (4)    primary coat. (5)