NOVELTY - A membrane electrode assembly (13) has an anode (11), a cathode (12) and an electrolytic membrane (10). The cathode includes a cathode catalyst layer (18) and cathode diffused layer (19) laminated on cathode catalyst layer. The cathode diffused layer has porous composite layer (19b) arranged on electroconductive porous base material (19a). The porous composite layer includes electroconductive carbon particle and water-repellent binding material. The diffused layer has through-holes having maximum pore diameter of 15-20.5 mu m and average stream flow pore diameter of 3-10.5 mu m.    USE - Membrane electrode assembly is used for fuel cell (claimed). Uses include but are not limited to power supply for portable small electronic devices, e.g. mobile telephone, notebook personal computer, digital still camera, electric scooter, motor vehicles, etc.    ADVANTAGE - The membrane electrode assembly provides fuel cell with excellent electric power generation characteristics and durability.    DETAILED DESCRIPTION - A membrane electrode assembly has an anode, a cathode and an electrolytic membrane arranged between anode and cathode. The cathode includes a cathode catalyst layer and cathode diffused layer laminated on cathode catalyst layer. The cathode diffused layer has an electroconductive porous base material, and porous composite layer arranged on one surface of electroconductive porous base material. The porous composite layer includes an electroconductive carbon particle and a water-repellent binding material. The cathode diffused layer has several through-holes. The through-hole has maximum pore diameter of 15-20.5 mu m and average stream flow pore diameter of 3-10.5 mu m by pore volume distribution measured by the half dry/bubble-point method. An INDEPENDENT CLAIM is included for fuel cell (1).    DESCRIPTION OF DRAWING(S) - The drawing shows the longitudinal cross-sectional view of fuel cell.    Fuel cell (1)    Electrolytic membrane (10)    Anode (11)    Cathode (12)    Membrane electrode assembly (13)    Cathode catalyst layer (18)    Cathode diffused layer (19)    Electroconductive porous base material (19a)    Porous composite layer (19b)