A hydrogen storage alloy suitable for a negative electrode of an on-board alkaline storage battery, an alkaline storage battery using this hydrogen storage alloy, and a vehicle; wherein a fine-grained hydrogen storage alloy is used for an alkaline storage battery that has a crystal structure of an A.sub.2B.sub.7-type structure as a main phase and is represented by a general formula: (La.sub.1-aSm.sub.a).sub.1-bMg.sub.bNi.sub.cAl.sub.dCr.sub.e (where suffixes a, b, c, d, and e meet the following conditions: 0a0.35, 0.15b0.30, 0.02d0.10, 0e0.10, 3.20c+d+e3.50, and 0<a+e), and an alkaline storage battery using this hydrogen storage alloy for a negative electrode. A vehicle also includes this alkaline storage battery as an electricity supply source for a motor.

A disclosed hydrogen-absorbing alloy has a composition represented by a formula La.sub.aR.sub.(b-a)Mg.sub.cZr.sub.dNi.sub.xAl.sub.yM.sub.z, wherein R is at least one rare earth element including Y but not including La, 0.10a0.40, 0.67b0.96, 0.01c0.30, 0.01d0.05, and b+c+d=1.00 are satisfied, M is at least one element selected from the group consisting of Co, Mn, Ag, and Sn, 3.10x3.80, 0.03 y0.25, 0z0.05, and 3.45x+y+z3.85 are satisfied, and the alloy includes, as crystal phases, four phases respectively having a Ce.sub.2Ni.sub.7 type structure, a Ce.sub.5Co.sub.19 type structure, a Pr.sub.5Co.sub.19 type structure, and a CaCu.sub.5 type structure, at specific proportions.