Provided is a nickel-zinc storage battery prepared, preferably, by winding into a whirlpool a sheet-like zinc electrode, a sheet-like nickel electrode and a separator with the separator interposed between the zinc and nickel electrodes, said zinc electrode being obtained by bonding under pressure to a collector a mixture sheet consisting of zinc oxide, zinc, bismuth oxide, calcium hydroxide and fluoroplastic, said nickel electrode being obtained by bonding under pressure an oxide of nickel to a collector together with a conductive material, said separator being obtained by coating on an alkali-resisting nonwoven fabric a mixture of polyvinyl alcohol and at least either of one selected from the group consisting of boric acids and metal oxides having low solubility to alkali solution and drying the nonwoven fabric thus coated.