A positive electrode plate (3) of a nickel-metal hydride battery contains nickel hydroxide particles (18), a coating layer (19) covering at least a part of the surface of each nickel hydroxide particle (18) and mainly composed of a cobalt compound having an average valence of cobalt more than 2, and Nb-based particles (15) and Y-based particles (16) distributed among the nickel hydroxide particles (18). A negative electrode plate (4) contains a hydrogen storage alloy having a Co content of not more than 2.0% by mass, a separator (5) contains a fiber having a sulfone group, and an alkaline electrolyte solution contains sodium hydroxide as the main solute.