It is an object of the present invention to provide a polymer electrolyte material which has excellent proton conductivity even under the conditions of a low humidity or a low temperature and is excellent in mechanical strength and fuel barrier properties, and which moreover can achieve high output, high energy density and long-term durability in forming a polymer electrolyte fuel cell therefrom, and a polymer electrolyte form article using the same and a method for producing the same, a membrane electrode assembly and a polymer electrolyte fuel cell, each using the same.The present invention employs the following means. Namely, the polymer electrolyte material of the present invention is a polymer electrolyte material including a constituent unit (A1) containing an ionic group and a constituent unit (A2) substantially not containing an ionic group, wherein a phase separation structure is observed by a transmission electron microscope and a crystallization heat measured by differential scanning calorimetry is 0.1 J/g or more, or a phase separation structure is observed by a transmission electron microscope and the degree of crystallinity measured by wide angle X-ray diffraction is 0.5% or more. Also, the polymer electrolyte form article, the membrane electrode assembly and the polymer electrolyte fuel cell of the present invention are characterized by being composed of such polymer electrolyte materials.