In order to obtain a nickel-metal hydride storage battery having a long cycle life and a low self-discharge rate, in a nickel-metal hydride storage battery comprising: a positive electrode containing nickel hydroxide; a negative electrode containing a hydrogen storage alloy; a separator interposed between the positive and negative electrodes; and an electrolyte comprising an aqueous alkaline solution, a water absorbent polymer, a water repellent and an aqueous alkaline solution are added into the separator. This battery can be produced with low cost.