NOVELTY - A membrane electrode assembly (1) consists of a proton-conductive electrolytic membrane (2), a cathode catalyst metal layer (3), an anode catalyst metal layer (4), a cathode diffused layer (5), and an anode diffused layer (6). The electrolytic membrane is provided with an internal electrode catalyst layer (20), a cathode-side electrolytic membrane (21), and an anode-side electrolytic membrane (25). Layer (20) contains an electrolyte composition, electroconductive fine particles which support a catalyst metal, and an electroconductive filler.    USE - Membrane electrode assembly is used in fuel cells e.g. solid polymer fuel cell. Uses include but are not limited to vehicles, industrial applications, electronic devices, and electric machines.    ADVANTAGE - The membrane electrode assembly has improved electric interengagement property with respect to cathode-side electrolytic membrane and internal electrode catalyst layer. Contact resistance with cathode-side electrolytic membrane which adjoins the internal electrode catalyst layer is reduced. The original function of internal electrode catalyst layer is exhibited. The assembly has gas permeation control function.    DETAILED DESCRIPTION - A membrane electrode assembly consists of a proton-conductive electrolytic membrane, a cathode catalyst metal layer joined to one surface of the electrolytic membrane in thickness direction, an anode catalyst metal layer joined to the other surface, a cathode diffused layer laminated at the outer side of the cathode catalyst metal layer in thickness direction, and an anode diffused layer laminated at the outer side of the anode catalyst metal layer. The electrolytic membrane is provided with an internal electrode catalyst layer, a cathode-side electrolytic membrane having electroconductivity and proton conductivity, and a proton-conductive anode-side electrolytic membrane. The internal electrode catalyst layer contains an electrolyte composition with proton conductivity, electroconductive fine particles which support a catalyst metal, and an electroconductive filler. The cathode-side electrolytic membrane is provided between the internal electrode catalyst layer and cathode catalyst metal layer for electrically connecting them. The anode-side electrolytic membrane is arranged between the internal electrode catalyst layer and anode catalyst metal layer.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the membrane electrode assembly. (Drawing includes non-English language text)    Membrane electrode assembly (1)    Electrolytic membrane (2)    Cathode catalyst metal layer (3)    Anode catalyst metal layer (4)    Cathode diffused layer (5)    Anode diffused layer (6)    Internal electrode catalyst layer (20)    Cathode-side electrolytic membrane (21)    Anode-side electrolytic membrane (25)