In order to provide a nickel-metal hydride storage battery capable of preventing the formation of a minute chemical short circuit between the positive and negative electrodes while exhibiting an excellent self-discharge resistance, a nickel positive electrode plate is formed by filling an active material mainly composed of a hydroxide of nickel into a porous sintered nickel substrate, followed by further forming a layer of a manganese compound containing manganese with a valence of 2 or more on the surface thereof, and an alkaline storage battery is configured by using this nickel positive electrode plate.