NOVELTY - Nickel (Ni)-metal hydride secondary cell comprises a container, and an electrode group hermetically contained in the container together with an alkaline electrolyte solution, the electrode group includes a separator, a negative electrode and a positive electrode, where the negative electrode contains a hydrogen absorbing alloy.    USE - The Ni-metal hydride secondary cell is useful in portable devices and hybrid electric vehicles.    ADVANTAGE - The Ni-metal hydride secondary cells have high capacity, superior environmental safety, and excellent in both self-discharge characteristics and cycle life characteristics.    DETAILED DESCRIPTION - Nickel (Ni)-metal hydride secondary cell comprises a container, and an electrode group hermetically contained in the container together with an alkaline electrolyte solution, the electrode group includes a separator, a negative electrode and a positive electrode, where the negative electrode contains a hydrogen absorbing alloy having a composition represented by a general formula: (RE1-xTx)1-yMgyNiz-aAla, the hydrogen absorbing alloy has a crystal structure in which an AB2 subunit and an AB5 subunit are superimposed one upon the other, and chromium (Cr) is substituted for part of the Ni.    RE=at least one element selected from Y, Sc and rare-earth elements;    T=at least one element selected from Zr, V and Ca; and    x, y, z and a=values respectively satisfying 0 less than or equal to x, 0.05 less than or equal to y less than or equal to 0.35, 2.8 less than or equal to z less than or equal to 3.9, and 0.10 less than or equal to a less than or equal to 0.25.    An INDEPENDENT CLAIM is included for a negative electrode included in a nickel-metal hydride secondary cell, comprising a hydrogen absorbing alloy having a composition represented by a general formula: (RE1-xTx)1-yMgyNiz-aAla, the hydrogen absorbing alloy has a crystal structure in which an AB2 subunit and an AB5 subunit are superimposed one upon the other, and Cr is substituted for part of the Ni.