PURPOSE: To obtain a long-life catalyst derived from Me-TAA (a metal complex of tetraazoanulene), of which the reduction overvoltage of oxygen is reduced.

CONSTITUTION: A metal complex shown by the formula (a general name, 6,13- dipyridyl-1,8-dihydrodibenzo[b, i][1, 4, 8, 11]tetraazacyclotetradecine) is supported by an electrode as a catalyst. As an electrolyte to be used with the resulting electrode catalyst, sulfuric acid, phosphoric acid, an aqueous Na2SO4 solution, an aqueous Na3PO4 solution, KOH or NaOH may be used. As an electrode material, carbon or a metal oxide can be used and, in the case of an acidic electrolyte, graphite powder, acetylene, activated carbon, iron, cobalt and perovskite type composite oxide are pref. used. The amount of the catalyst is pref. 0.001W10wt% based on the electrode material powder. Me shows Co, Fe, Ni or Mn.