NOVELTY - Composite catalyst comprises an inorganic oxide (11), and a catalytic metal (12), where a compound having a functional group including an amino group or a thiol group is bonded to a surface of the inorganic oxide, and the catalytic metal is bonded to the functional group.    USE - The composite catalyst is useful in: an anode and cathode of a membrane electrode assembly, which is useful in a fuel cell of fuel cell power generation system (all claimed), where the fuel cell is a polymer electrolyte fuel cell or a direct methanol fuel cell; and exhaust gas purification in a vehicle.    ADVANTAGE - The composite catalyst: has improved durability; provides strong adsorbability of the catalytic metal complex to the surface of the metal oxide; makes an amount of the adsorbed catalytic metal complex large; increases the amount of the catalytic metal supported per unit surface area of the metal oxide; reduces the thickness of the electrodes; improves the diffusion of fuel; increases output density of the fuel cell; prevents transfer and aggregation of the catalytic metal particles; and can stably support the catalytic metal particles at a high density on the metal oxide.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) an anode comprising the composite catalyst;    (2) a cathode comprising the composite catalyst;    (3) a membrane electrode assembly comprising the anode and cathode containing the composite catalyst, and an electrolyte membrane having proton conductivity, disposed between the anode and the cathode;    (4) a fuel cell comprising the membrane electrode assembly, a constituent member for supplying fuel and oxygen, and a collector member for outputting generated electricity;    (5) a fuel cell power generation system comprising the fuel cell; and    (6) producing the composite catalyst comprising bonding a compound having a functional group including an amino group or a thiol group to a surface of an inorganic oxide, bonding a metal complex containing a catalytic metal to the functional group, and reducing the metal complex to the catalytic metal.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of a structure of a composite catalyst.    Inorganic (Metal) oxide (11)    Catalytic metal (12)    Carbon (13)