A negative electrode plate of a nickel hydrogen storage battery includes a nonaqueous polymer binder and has an effective surface area per unit capacity of 70 cm<2>/Ah or more. The density of the first and second separators between positive and negative electrode plates ranges from 450 kg/m<3 >to 600 kg/m<3>. The nonwoven fabrics of the separators are formed by combining microfibers and compound fibers through melting portions of the compound fibers. The fibers have a virtually circular cross-section. The microfibers and the compound fibers have a diameter ranging from 1 mum to less than 5 mum and a diameter ranging from 5 mum to 15 mum, respectively. The proportion of the microfibers to whole fibers ranges from 10 percent by mass to 20 percent by mass. At least one of the nonwoven fabrics of the separators is subjected to sulfonation treatment.