TECHNOLOGY FOCUS - POLYMERS - Preferred Film: The polyphenylene ether resin is oriented at random in plane perpendicular to film-thickness direction. The breadth of the polyphenylene ether resin is 0.01-100 microns. The length-breadth ratio of the polyphenylene ether resin is 1-10000 microns. The polyphenylene ether resin has a very small connection portion to which a structure is connected mutually. The size of the connection portion is 0.01-10 microns. The proton exchange resin is a fluorine type polymer electrolyte. The polymeric electrolyte film has a swelling rate of 100-105%, when the swelling rate after neglecting the film at 80degreesC under water for 1 hour is plotted along X-axis and swelling rate of film after neglecting for 8 hours at 25degreesC and 20% RH is plotted along Y-axis. The ratio of the swelling rate along Y-axis and X-axis, is 0.5-1.5. Preferred Method: The cast liquid is supplied to the nozzle of a spray gun, and vortex flow of compression gas is generated. Crushing atomization of the cast liquid is performed and the liquid is sprayed conically towards a support surface to form the polymeric electrolyte film. Preferred Assembly: The polymeric electrolyte film or polyelectrolyte laminated film is formed only in the portion which touches the edge of anode catalyst layer and cathode catalyst layer. Preferred Fuel Cell: The polymeric electrolyte film or polyelectrolyte laminated film is provided in inlet portion and/or exit portion of the fuel cell such as anode gas inlet portion, anode gas outlet portion, cathode gas inlet portion and/or cathode gas exit portion. EXAMPLE - A perfluoro carbon polymer of tetrafluoro ethylene was contacted with potassium hydroxide and dimethyl sulfoxide aqueous solution, at 60degreesC for 4 hours. Hydrolysis processing was performed, followed by immersing in water for 4 hours at 60degreesC and immersing in 2 N hydrochloric acid aqueous solution for 3 hours at 60degreesC. Washing was performed followed by drying, to obtain perfluoro sulfonic-acid polymer (PFS) of ion exchange capacity 1.41 mEq/g. The obtained polymer (PFS) was sealed in an autoclave containing water and ethanol at mass ratio 50:50. Temperature was maintained at 180degreesC for 5 hours, followed by cooling. On the other hand, poly(2,6-dimethyl-1,4-phenylene ether) (PPE) of intrinsic viscosity 0.5 g/dl at 30degreesC was mixed with toluene, to obtain a solution. The obtained solution was added to the autoclave and stirred, to obtain a cast liquid containing 4.4 mass% of PFS and 0.7 mass% of PPE. 30 g of obtained cast liquid was sprayed on a metal plate preheated at 60degreesC. Heat processing was performed to obtain a polymeric electrolyte film of thickness 20 microns. Acicular PPE of breadth 0.01-4 microns and aspect ratio 1-400, was dispersed uniformly and oriented perpendicularly in film-thickness direction.