NOVELTY - A hydrogen storage alloy (A1) for alkaline storage battery comprises: a composition (I) expressed by lanthanum/another rare earth element/magnesium/nitrogen/aluminum/metal selected from cobalt, manganese or zinc in a specific ratio; and a main phase of an A5B19 type crystal structure, where a ratio of X/Y' of the concentration ratio X ((%) of aluminum to nickel (Al/Ni)) in a surface layer and the concentration ratio Y' (Al/Ni) (%) in a bulk layer, is 0.36-0.85.    USE - As a hydrogen storage alloy for alkaline storage battery (claimed), that is suited for applications requiring high current discharge (high power applications), for hybrid electric vehicles, and pure electric vehicles.    ADVANTAGE - The hydrogen storage alloy for an alkaline storage battery improves output power by pulverization of alloy in the initial stage of partial charge and discharge cycles, and maintains its surface condition to greatly improve the amount of lifetime work. The A5B19 type crystal structure reduces the trouble of eluting Al from the hydrogen storage alloy into an alkaline electrolyte, thereby improving the durability of the battery.    DETAILED DESCRIPTION - A hydrogen storage alloy (A1) for alkaline storage battery comprises: a composition expressed by formula LaxRyMg1-x-yNin-m-vAlmTv (I); and a main phase of an A5B19 type crystal structure, where a ratio of X/Y' of the concentration ratio X ((%) of aluminum to nickel (Al/Ni)) in a surface layer and the concentration ratio Y' (Al/Ni) (%) in a bulk layer, is 0.36-0.85.    R=element selected from rare earth elements other than La but including Y;    T=Co, Mn, or Zn;    x=0.17-0.64;    n=3.5-3.8;    m=0.06-0.22;    v= greater than or equal to 0.    INDEPENDENT CLAIMS are included for the following:    (1) an alkaline storage battery (B1) comprising: an electrode group including a hydrogen storage alloy negative electrode including negative electrode active material of a hydrogen storage alloy, a nickel positive electrode including positive electrode active material mainly containing nickel hydroxide, and a separator; an alkaline electrolyte; and an outer can housing the electrode group and the alkaline electrolyte, the hydrogen storage alloy (A1), and the hydrogen storage alloy negative electrode retaining the alkaline electrolyte in a retention amount (Z1) of 95-125 mg per gram of the hydrogen storage alloy; and    (2) an alkaline storage battery system (S1) comprising: the alkaline storage battery (B1), and a partial charge and discharge control apparatus performing such control that the alkaline storage battery is charged and discharged only within a state of charge (SOC) of 20-80%.