A sealed storage battery comprises a positive electrode including a metallic oxide as an active material, a negative electrode including hydrogen-storage-alloy powder capable of electrochemically charging and discharging hydrogen as an active material, an alkaline electrolyte, and two separators (12a and 1 2b) for absorbing and retaining the alkaline electrolyte. The hydrogen-storage-alloy power has a crystal structure and is provided with numerous irregularities on the surface thereof, and has SF-value of 2.5 or below, which SF-value represents a plateau characteristic of equilibrium pressure of released hydrogen. The numerous irregularities on the surface of the alloy powder cause oxygen being generated from the positive electrode to be eliminated promptly.