A nickel metal hydride secondary battery, comprising a container and an electrode assembly housed in the container together with an alkaline electrolytic solution, characterized in that the electrode assembly is such that a positive electrode including a positive electrode mixture and a negative electrode including a negative electrode mixture are superimposed with a separator interposed therebetween; the positive electrode mixture includes nickel hydroxide having formed a solid solution with zinc as a positive electrode active material and zinc oxide as a positive electrode additive; the negative electrode mixture includes hydrogen absorbing alloy particles and a negative electrode additive; the negative electrode additive is a composite in which yttrium fluoride is supported on carbon black; and a surface of the hydrogen absorbing alloy particles is coated partially with the composite, wherein the zinc forms a solid solution at a concentration of 3.5 parts by mass or more and 4.5 parts by mass or less with respect to 100 parts by mass of the nickel hydroxide; the zinc oxide is added at a concentration of 0.5 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the positive electrode active material; and the yttrium fluoride accounts for 0.1 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the hydrogen absorbing alloy, and wherein the hydrogen absorbing alloy has a composition represented by formula shown below: Ln 1-x Mg x Ni y-z Al z wherein Ln represents at least one element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y, Ti and Zr, and the subscripts x, y, and z satisfy the relationship represented as 0.05 ≤ x ≤ 0.30, 2.8 ≤ y ≤ 3.8, and 0.05 ≤ z ≤ 0.30, respectively. the electrode assembly is such that a positive electrode including a positive electrode mixture and a negative electrode including a negative electrode mixture are superimposed with a separator interposed therebetween; the positive electrode mixture includes nickel hydroxide having formed a solid solution with zinc as a positive electrode active material and zinc oxide as a positive electrode additive; the negative electrode mixture includes hydrogen absorbing alloy particles and a negative electrode additive; the negative electrode additive is a composite in which yttrium fluoride is supported on carbon black; and a surface of the hydrogen absorbing alloy particles is coated partially with the composite, the positive electrode mixture includes nickel hydroxide having formed a solid solution with zinc as a positive electrode active material and zinc oxide as a positive electrode additive; the negative electrode mixture includes hydrogen absorbing alloy particles and a negative electrode additive; the negative electrode additive is a composite in which yttrium fluoride is supported on carbon black; and a surface of the hydrogen absorbing alloy particles is coated partially with the composite, wherein the zinc forms a solid solution at a concentration of 3.5 parts by mass or more and 4.5 parts by mass or less with respect to 100 parts by mass of the nickel hydroxide; the zinc oxide is added at a concentration of 0.5 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the positive electrode active material; and the yttrium fluoride accounts for 0.1 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the hydrogen absorbing alloy, and the zinc forms a solid solution at a concentration of 3.5 parts by mass or more and 4.5 parts by mass or less with respect to 100 parts by mass of the nickel hydroxide; the zinc oxide is added at a concentration of 0.5 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the positive electrode active material; and the yttrium fluoride accounts for 0.1 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the hydrogen absorbing alloy, and wherein the hydrogen absorbing alloy has a composition represented by formula shown below: Ln 1-x Mg x Ni y-z Al z wherein Ln represents at least one element selected from the group consisting of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y, Ti and Zr, and the subscripts x, y, and z satisfy the relationship represented as 0.05 ≤ x ≤ 0.30, 2.8 ≤ y ≤ 3.8, and 0.05 ≤ z ≤ 0.30, respectively.