The present invention provides a nickel-zinc battery of an inside-out structure, that is, a battery comprising a positive electrode containing beta-type nickel oxyhydroxide and a negative electrode containing zinc and having a similar structure to an alkali manganese battery, in which the beta-type nickel oxyhydroxide consists of substantially spherical particles, mean particle size of which is within a range from 19 .mu.m to a maximum of 40 .mu.m, the bulk density of which is within a range from 1.6 g/cm.sup.3 to a maximum of 2.2 g/cm.sup.3, tap density of which is within a range from 2.2 g/cm.sup.3 to a maximum of 2.7 g/cm.sup.3, specific surface area which based on BET method is within a range from 3 m.sup.2/g to a maximum of 50 m.sup.2/g, and the positive electrode of the nickel zinc battery contains graphite powder, where the weight ratio of graphite powder against a total weight of the positive electrode is defined within a range from 4% to a maximum of 8%.