An outer packaging material for electric storage device having a structure comprising at least a substrate layer, an adhesion layer, a metal foil layer, a sealant adhesion layer, and a sealant layer laminated in this order, wherein the substrate layer is one made of a polyamide film having a hot water shrinkage rate at 95°C of less than 5% and a hot shrinkage rate at 180°C of 4 to 16%, or a polyester film having a hot water shrinkage rate at 95°C of less than 5% and a hot shrinkage rate at 180°C of 10 to 25%, wherein the hot water shrinkage rate at 95°C and the hot shrinkage rate at 180°C are each determined using a test piece obtained by cutting the substrate layer to a size of 10 cm in length × 10 cm in width, and determining dimensions X in the longitudinal and the transverse directions of the test piece; for determining the hot water shrinkage rate at 95°C, the test piece is immersed in hot water at 95°C for 30 minutes, the dimensions Y in the longitudinal and transverse directions of the test piece after the immersion treatment in hot water are measured, and the hot water shrinkage rate at 95°C is calculated based on equation below as an average value of the dimensional variation ratios in the two directions; for determining the hot shrinkage rate at 180°C, the test piece is heated in an oven of 180°C for 30 minutes, the dimensions Y in the longitudinal and transverse directions of the test piece after the heating treatment in the oven are measured, and the hot shrinkage rate at 180°C is calculated based on equation below as an average value of the dimensional variation ratios in the two directions; Rate of dimensional change % = X − Y / X * 100 wherein X is a dimension prior to the immersion treatment in hot water or prior to the heating treatment in the oven, and Y is a dimension after the immersion treatment in hot water or after the heating treatment in the oven, characterized in that the outer packaging material for the electric storage device further comprises an easy adhesion treatment layer having a thickness of 0.02 to 0.5 μm provided between the substrate layer and the adhesion layer. at least a substrate layer, an adhesion layer, a metal foil layer, a sealant adhesion layer, and a sealant layer laminated in this order, wherein the substrate layer is one made of a polyamide film having a hot water shrinkage rate at 95°C of less than 5% and a hot shrinkage rate at 180°C of 4 to 16%, or a polyester film having a hot water shrinkage rate at 95°C of less than 5% and a hot shrinkage rate at 180°C of 10 to 25%, wherein the hot water shrinkage rate at 95°C and the hot shrinkage rate at 180°C are each determined using a test piece obtained by cutting the substrate layer to a size of 10 cm in length × 10 cm in width, and determining dimensions X in the longitudinal and the transverse directions of the test piece; for determining the hot water shrinkage rate at 95°C, the test piece is immersed in hot water at 95°C for 30 minutes, the dimensions Y in the longitudinal and transverse directions of the test piece after the immersion treatment in hot water are measured, and the hot water shrinkage rate at 95°C is calculated based on equation below as an average value of the dimensional variation ratios in the two directions; for determining the hot shrinkage rate at 180°C, the test piece is heated in an oven of 180°C for 30 minutes, the dimensions Y in the longitudinal and transverse directions of the test piece after the heating treatment in the oven are measured, and the hot shrinkage rate at 180°C is calculated based on equation below as an average value of the dimensional variation ratios in the two directions; Rate of dimensional change % = X − Y / X * 100 wherein X is a dimension prior to the immersion treatment in hot water or prior to the heating treatment in the oven, and Y is a dimension after the immersion treatment in hot water or after the heating treatment in the oven, characterized in that the outer packaging material for the electric storage device further comprises an easy adhesion treatment layer having a thickness of 0.02 to 0.5 μm provided between the substrate layer and the adhesion layer.