NOVELTY - A modified aromatic amine compound is obtained by subjecting a composition including a metallic component, and an aromatic amine polymer (I) to heat treatment, radiation irradiation treatment, and discharge treatment. The polymer is obtained by intermolecularly joining a nitrogen atom, which forms an amine group that joins with aromatic ring in a molecule of the compound, and a carbon atom which forms aromatic ring in another molecule of the compound.    USE - Modified aromatic amine is used for redox catalyst and electrode catalyst used for fuel cell (all claimed). Uses include but are not limited to polymer electrolyte fuel cell used for mobile machine, motor vehicles, domestic appliances, mobile telephones, and portable personal computer.    ADVANTAGE - The catalyst containing the modified aromatic amine compound, has excellent stability and oxygen reduction property.    DETAILED DESCRIPTION - A modified aromatic amine compound is obtained by subjecting a composition including a metallic component, and an aromatic amine polymer of formula: Ar'-(NH-R1)n (I) to heat treatment, radiation irradiation treatment, and discharge treatment. The polymer is obtained by intermolecularly joining a nitrogen atom, which forms an amine group that joins with aromatic ring in a molecule of the compound, and a carbon atom which forms aromatic ring in another molecule of the compound.    Ar'=monocyclic aromatic hydrocarbon ring having substituent group, optionally substituted monocyclic aromatic heterocyclic ring, or optionally substituted polycyclic aromatic ring;    R1=H, halo, hydroxy, carboxy, mercapto, sulfonate, amine, nitro, phosphonate, silyl substituted by 1-4C alkyl, optionally branched 1-50C alkyl, 3-50C cyclic alkyl, alkenyl, alkynyl, alkoxy, 6-60C aryl, 7-50C aralkyl, or monovalent heterocyclyl;and    n=1 or more.    At least one of carbon atoms forming aromatic ring has hydrogen atom or halo group.    DESCRIPTION OF DRAWING(S) - The drawing shows a longitudinal cross-sectional view of fuel cell containing he modified aromatic amine compound.    Fuel cell (10)    Electrolytic membrane (12)    Catalyst layers (14a,14b)    Gas-diffusion layers (16a,16b)    Separators (18a,18b)    Membrane-electrode assembly (20)