An alkaline dry battery including nickel oxyhydroxide and manganese dioxide as positive electrode active materials. The nickel oxyhydroxide is a solid solution including at least manganese and cobalt. The content of the manganese is 5.2×10−2 to 7.5×10−2 moles per mole of the nickel oxyhydroxide, and the content of the cobalt is 0.5×10−2 to 2.0×10−2 moles. The alkaline dry battery maintains excellent heavy-load discharge characteristics, exhibits suppressed polarization during heavy-load pulse discharge to improve the operational stability of digital devices, and has high reliability with respect to leakage resistance and safety under short-circuit conditions.