PURPOSE: To prevent drop of sealing ability at high temperature by sealing an alkaline battery with a gasket comprising polysulfone resin and a sealing layer formed by sealant prepared by dissolving asphalt in nonpolar cyclic hydrocarbon solvent.

CONSTITUTION: A sealing part between an outer can 3 and a sealing can 4 of a sealed battery using alkaline electrolyte is sealed with a gasket 1 comprising polysulfone resin and a sealing layer 2 formed by sealant prepared by dissolving asphalt in nonpolar cyclic hydrocarbon solvent such as decalin or cyclohexane. Oxidation and heat deformation of the gasket 1 are retarded, and the solvent increases solubility of asphalt and gives no chemical and physical effect to polysulfone resin. Therefore, sealing ability and heat resistance of a battery are increased and operating temperature of the battery is enlarged.