The invention is directed to provide a cylindrical nickel-hydrogen storage battery having high discharge power densities both at SOC 50% and at SOC 20%. In an alkaline storage battery according to an embodiment of the invention, a nickel positive electrode formed into a rectangular shape has a short side length of X and a long side length of Y, the ratio (Y/X) of the long side length to the short side length is 25 or more and 40 or less (25≦Y/X≦40), the short side length is 25 mm or more and 45 mm or less (25 mm≦X≦45 mm), and the battery capacity is 3 Ah or more and 7 Ah or less.