The present invention provides a hydrogen absorbing alloy containing as a principal phase at least one phase selected from the group consisting of a second phase having a rhombohedral crystal structure and a first phase having a crystal structure of a hexagonal system excluding a phase having a CaCu.sub.5 type structure, wherein a content of a phase having a crystal structure of AB.sub.2 type is not higher than 10% by volume including 0% by volume and the hydrogen absorbing alloy has a composition represented by general formula (1) given below: R.sub.1-a-bMg.sub.aT.sub.bNi.sub.Z-X-Y-.alpha.M1.sub.XM2.sub.YMn.sub..alp- ha. (1).