To provide an oxygen reduction electrocatalyst showing high oxygen reduction activity, while capable of being manufactured at a low cost, and to provide an oxygen reduction electrode using this, as well as, a battery.

The oxygen reduction electrocatalyst is constituted of a composite material to which cation comes to be interposed between sheets of a sheet-stacked region made of nanosheets of a transition metal oxide. In the oxygen reduction electrocatalyst, a transition metal constituting the transition metal oxide, is at least one preferably selected from among a group consisting of Ti, Ta, Nb, Ru, Mn, V, W, Mo, and Co. Also, in the oxygen reducible electrocatalyst, the composite material, is preferred to contain a structure with nanosheets laminated at random, or a structure with a cross-section of nanosheets made round into a spiral form.