The invention relates to packaging material, a case, and a power storage device. The packaging material of the present invention includes a heat-resistant resin layer 2 as an outer-side layer, a heat-meltable resin layer 3 as an inner-side layer, and a metal foil layer 4 interposed between these layers. The heat-resistant resin layer 2 is formed of a heat-resistant resin film having a hot-water shrinkage rate of 1.5 to 12%, and the heat-resistant resin layer 2 and the metal film layer 4 are bonded through an outer-side adhesive layer 5. The adhesive layer 5 is formed by a urethane adhesive agent containing a polyol, a polyfunctional isocyanate compound, and an aliphatic compound containing a plurality of functional groups capable of reacting with an isocyanate group with a molecule. Thereby, a packaging material can be provided in which excellent formability can be ensured, and delamination can be suppressed sufficiently without causing fine holes, etc. even when deep-drawing is performed with great depth.