A packaging material for a power storage device, having a structure in which at least a substrate layer, a metallic foil layer with an anti-corrosion treatment layer being disposed on one face or both faces thereof, an adhesive layer or an adhesive resin layer, and a sealant layer are laminated in this order, wherein at least one layer of the adhesive resin layer and the sealant layer comprises a polyolefin-based resin, and an additive compound with an SP value of 11.0 (cal/cm3)1/2 or more and 20.0 (cal/cm3)1/2 or less.