An electrolyte emulsion, comprising: an aqueous medium; and a fluoropolymer electrolyte dispersed in the aqueous medium, the fluoropolymer electrolyte having a monomer unit that has an SO 3 Z group, wherein Z is an alkali metal, an alkaline-earth metal, hydrogen, or NR 1 R 2 R 3 R 4 , wherein R 1 , R 2 , R 3 , and R 4 each are individually a C1-C3 alkyl group or hydrogen, the electrolyte having an equivalent weight (EW) of 250 or more and 700 or less, a proton conductivity at 110°C and relative humidity 50%RH of 0.10 S/cm or higher, and a ratio (the number of SO 2 F groups) / (the number of SO 3 Z groups) of 0 to 0.01, and the electrolyte being a spherical particulate substance having an average particle size of 10 to 500 nm, wherein the fluoropolymer electrolyte has a distance between ionic clusters of 0.1 nm or higher and 2.6 nm or lower at 25°C and relative humidity 50%RH calculated by small angle X-ray measurement based on the following formula : α = λ / 2 / sin θm wherein d is a distance between ionic clusters, λ is an incident X-ray wavelength used in the small angle X-ray measurement, and θm is a Bragg angle which indicates a peak, and wherein the average particle size is determined by applying the electrolyte emulsion to a glass substrate; followed by removing the aqueous medium to provide an aggregate and observing the aggregate using a scanning or transmission electron microscope, or an atomic force microscope; wherein 20 or more particles in the obtained image each are measured for the length of its major and minor axes; and wherein the average value of the lengths of the major and minor axes is treated as the average particle size. an aqueous medium; and a fluoropolymer electrolyte dispersed in the aqueous medium, the fluoropolymer electrolyte having a monomer unit that has an SO 3 Z group, wherein Z is an alkali metal, an alkaline-earth metal, hydrogen, or NR 1 R 2 R 3 R 4 , wherein R 1 , R 2 , R 3 , and R 4 each are individually a C1-C3 alkyl group or hydrogen, the electrolyte having an equivalent weight (EW) of 250 or more and 700 or less, a proton conductivity at 110°C and relative humidity 50%RH of 0.10 S/cm or higher, and a ratio (the number of SO 2 F groups) / (the number of SO 3 Z groups) of 0 to 0.01, and the electrolyte being a spherical particulate substance having an average particle size of 10 to 500 nm, wherein the fluoropolymer electrolyte has a distance between ionic clusters of 0.1 nm or higher and 2.6 nm or lower at 25°C and relative humidity 50%RH calculated by small angle X-ray measurement based on the following formula : α = λ / 2 / sin θm wherein d is a distance between ionic clusters, λ is an incident X-ray wavelength used in the small angle X-ray measurement, and θm is a Bragg angle which indicates a peak, and wherein the average particle size is determined by applying the electrolyte emulsion to a glass substrate; followed by removing the aqueous medium to provide an aggregate and observing the aggregate using a scanning or transmission electron microscope, or an atomic force microscope; wherein 20 or more particles in the obtained image each are measured for the length of its major and minor axes; and wherein the average value of the lengths of the major and minor axes is treated as the average particle size. <EOS>