NOVELTY - The material (1) has a heat-resistant resin stretched film outer layer (2) which is laminated on surface of an aluminum foil layer (4) whose outer surface is laminated with a non-stretched thermoplastic resin film inner layer (3) with adhesive layers (5,6). Adhesive strength between width of inner layer and aluminum foil layer is 4-30N/15mm and adhesive strength width of outer layer and aluminum foil layer is 2-14N/15mm, such that sealing strength of two layers of thermoplastic resin films are arranged one above other and are heat-sealed without exceeding the width of 110N/15mm.    USE - Outer packaging material for lithium ion secondary battery used in notebook computer, video camera, cell phones and electric car.    ADVANTAGE - The adhesive strength between width of inner layer and aluminum foil layer is 4-30N/15mm and adhesive strength width of outer layer and aluminum foil layer is 2-14N/15mm, such that sealing strength of two layers of thermoplastic resin films are arranged one above other and are heat-sealed without exceeding the width of 110N/15mm, such that the gas is introduced into the battery main portion by overcharging and overheating of battery can be avoided. The increase in inner pressure of the exterior packaging material can be avoided. The need of safety valve can be avoided, hence complex productivity can be relieved. The sufficient sealing properties can be achieved. The tearing of the outer packaging material by internal can be prevented. The breakage of the battery case by an increase in the internal pressure can be avoided. The adhesive strength setting can be easily performed, by changing the adhesive agent. The cracking of the battery case by increasing the internal pressure can be prevented.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for battery.    DESCRIPTION OF DRAWING(S) - The drawings show the cross-sectional views of the outer packaging material.    Outer packaging material (1)    Heat-resistant resin stretched film outer layer (2)    Non-stretched thermoplastic resin film inner layer (3)    Aluminum foil layer (4)    Adhesive layers (5,6)