The present invention provides a method for manufacturing a nickel-hydrogen storage battery in which the durability of a negative-electrode plate, and hence the battery, is improved and an increase in the internal resistance is suppressed. This method for manufacturing a nickel-hydrogen storage battery is provided with a negative-electrode-plate-producing step in which a negative electrode plate is produced by applying a mixture of hydrogen-storing alloy powder and Y2O3 powder to a base material, and a solution-injecting step. In the negative-electrode-plate-producing step, the mixture to be used is produced by mixing the hydrogen-storing alloy powder and the Y2O3 powder in an addition ratio at which a first product (S1) obtained by multiplying the half width (HW) of a peak of a (222) plane and the addition ratio (P) of the Y2O3 powder added into the mixture falls into a range of 0.03 to 0.17 deg wt%, the peak of the (222) plane being observed by the powder X-ray diffraction of the Y2O3 powder.