Provided is an alkaline secondary battery including: a stacked-cell battery in which multiple single cell elements having a configuration of an alkaline secondary battery are stacked; and a box-shaped case made of resin in which the stacked-cell battery is housed vertically. The box-shaped case has a bottom, a pair of long-side walls parallel to the stacked-cell battery, a pair of short-side walls perpendicular to the stacked-cell battery, and a lid part. The lid part has a vulnerable portion having a smaller thickness than other portions of the lid part, the thickness of the vulnerable portion is 0.1 to 1.0 mm, and a proportion of an area of the vulnerable portion with respect to a total area of the lid part in a plan view is 10 to 40%.