A micro porous layer 3a and a catalyst layer 3b are integrated into a sheet so that a fuel cell electrode sheet 3 is formed. The electrode sheet 3 is obtained by applying an MPL ink containing a carbon material and a binder to a supporting sheet S and heat-treating the ink, and applying a catalyst ink containing a catalyst to the obtained micro porous sheet 3a and drying it. An electrode assembly 1 in which the electrode sheets 3 are laminated onto both sides of a solid polymer electrolyte membrane 2, is obtained by laminating the electrode sheets 3 formed on the supporting sheets S to the solid polymer electrolyte membrane 2, and thereafter peeling off the supporting sheets S.