A material for the positive electrode of a silver oxide battery is provided that increases the discharge capacity of the battery. The positive electrode material is a conductive composite oxide represented by the general formula AgxNiyO2, in which X/Y is greater than 1 and does not exceed 1.9, and by the general formula AgxNiyMzO2, in which M represents at least one of Cu and Bi, X/(Y+Z) is greater than 1 and does not exceed 1.9, and Z does not exceed 0.4. These conductive oxides contain almost no free Ag2O and have a crystal structure similar to that of AgNiO2. As a result, the excess Ag—Ni oxide is conductive and has a high discharge capacity.