PURPOSE: To produce a platinum black air cathode that can economically use an active component, by constituting the electrode of a hydrophobic base layer consisting of granular carbon and hydrophobic polymer and an electrolytic porous active layer contg. fine powder platinum catalyst particles and halogenated polymer binder.

CONSTITUTION: The hydrophobic base layer, which is conductive and gas-permeable is prepd. by homogeneously and uniformly blending the powdery carbon (a grain size of about <0.3μ) and the hydrophobic polymer by using a halocarbon polymer as a binder so as to contain about 20 to 60wt.% hydrophobic polymer (various vinyl resin, etc.). The electrolytic porous active layer is also prepd. by homogeneously blending the halogenated polymer binder and the fine powder platinum catalyst particles and uniformly distributing the halogenated polymer binder over the entire part in such a manner that the former consists of about 0.1 to 10wt.% and the balance the latter. The base layer and the active layer are than sintered under pressure with the suitable polymer as an intermediate layer to obtain the electrode structure capable of economically using the active components without impairing the perfectness on the structure.