NOVELTY - An oxygen reduction catalyst comprises carbon, titanium, nitrogen, and oxygen as main element in ratio of 1:more than 0 to 7:more than 0.01 to 2:more than 0.05 to 3. In an X-ray powder diffraction examination using a copper-K alpha line, the oxygen reduction catalyst shows a peak in each of regions a and b comprising 2 theta angle of 42-43 degrees , 36.5-37 degrees , 25-26 degrees , and 27-28 degrees , respectively with respect to regions a to d, and the maximum-peak intensities Ia, Ib, Ic, and Id respectively for the regions a to d satisfies specific relations.    USE - Oxygen reduction catalyst is used as electrode catalyst, and ink for catalyst layer for electrode for membrane electrode assembly for polymer electrolyte fuel cell (all claimed). Uses include but are not limited to portable information terminal, motor vehicles, domestic electrical appliance, agricultural apparatus, electronic device, mobile telephone, street light, interior lighting, signal apparatus, outdoor generator etc.    ADVANTAGE - The oxygen reduction catalyst has high catalytic activity. The polymer electrolyte fuel cell provided using the membrane electrode assembly obtained using the oxygen reduction catalyst has excellent durability.    DETAILED DESCRIPTION - An oxygen reduction catalyst comprises titanium, carbon, nitrogen, and oxygen as main element. In an X-ray powder diffraction examination using a copper-K alpha line, the oxygen reduction catalyst shows a peak in each of regions a and b comprising 2 theta angle of 42-43 degrees , 36.5-37 degrees , 25-26 degrees , and 27-28 degrees , respectively with respect to regions a to d, and the maximum-peak intensities Ia, Ib, Ic, and Id respectively for the regions A to D satisfies relations: Ia is more than Ib, and 0.3 less than or equal to (Ia/(Ia+Ic+Id)) less than or equal to 1. INDEPENDENT CLAIMS are included for the following:    (1) manufacture of oxygen reduction catalyst, which involves mixing titanium-containing compound, nitrogen-containing organic compound, and solvent, obtaining catalyst-precursor solution (I), removing the solvent from the obtained catalyst-precursor solution, obtaining solid content residue (II), and heat processing the obtained solid content residue at 900-1400 degrees C (II);    (2) ink, which includes oxygen reduction catalyst;    (3) catalyst layer, which is obtained using the ink;    (4) electrode, which has catalyst layer and gas diffusion layer; and    (5) membrane electrode assembly, which has electrolytic membrane between anode and cathode containing catalyst layer.