The present invention relates to a packaging material for a power storage device, the packaging material having a structure in which at least a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer are laminated in this order, wherein the substrate protective layer is a cured product of a raw material containing a polyester resin and a polyisocyanate, a ratio [NCO]/[OH] is 5 to 60, where [OH] is the number of moles of hydroxyl groups in the polyester resin, and [NCO] is the number of moles of isocyanate groups in the polyisocyanate, and the polyester resin has a hydroxyl value of 10 to 70 KOHmg/g.