The hydrogen storage alloy, a hydrogen storage alloy electrode and a secondary battery

The present invention provides a chemical composition represented by the formula M1tM2uM3vCawMgxNiyM4z (wherein, 16 × (d-1.870) / (dr) ≤v≤16 × (d-1.860) / (dr), 1.6≤w≤3.2,4.1≤x≤5.1, 3.2≤ (y + z) / (t + u + v + w + x) ≤3.4, t + u + v + w + x + y + z = 100, M1 is selected from La, Pr, Nd 1 or two or more kinds of elements, M2 is selected from V, Nb, Ta, Ti, Zr, 1 or two or more kinds of elements of Hf, M3 is selected from Sm, Gd, Tb, Dy, Ho, Er, or two or more elements of Tm, Yb, Lu 1 Species, M4 is selected from Co, Mn, Al, Cu, Fe, Cr, Zn 1 or two or more kinds of elements, d is selected as M1 the average radius of a hydrogen atom of an element, an average atomic radius r is selected as the element M3.) represented by storage alloy electrode using the same and a secondary battery.