A power storage device packaging material including a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer, and a sealant layer in this order, wherein the substrate protective layer is made of a cured curable resin containing a plurality of types of particles having different average particle sizes, the curable resin contains a polyol component as a base resin and a polyisocyanate component as a hardener, and when, particles with a large average particle size are referred to as a large filler and particles with small average particle size are a small filler, the average particle size of the large filler is 10 μm or more, and the average particle size of the small filler is 1 μm or more, and an amount of the large filler is 3 mass % or more, and an amount of the small filler contained is 5 mass % or more.