Alkaline battery and battery pack

The invention provides a highly reliable alkaline battery having a large capacity, in which an internal short-circuit is not caused, even when the battery case falls down, then receives an impact and thus is deformed. A positive electrode and a gelled negative electrode are stored with a separator interposed therebetween in a battery case and an opening portion of the battery case is sealed with a gasket. The battery case is formed so that a thickness of a body portion thereof is smaller than a thickness of an opening portion thereof, the gasket includes a center portion, an outer circumference portion and a connection portion, an edge portion of the separator is in contact with the connection portion and bent toward the center portion and contact part of the edge portion with the connection portion has a length in a range of 1.5 mm to 2.5 mm.