To provide a technique for a battery-packaging material including a film-like laminate arranged by laminating at least a base layer, an adhesion layer, a metal layer and a sealant layer in turn, whichenables the further increase in the resistance against an electrolyte because of the base layer arranged to include a polyester film, but is hard to form no crack nor pin hole when shaping the base layer including a polyester film, and which brings about superior formability. A battery-packaging material comprises a laminate arranged by laminating at least, a base layer, an adhesion layer, a metal layer and a sealant layer in turn. The base material layer is formed of a biaxially stretched film including at least a polyester resin layer and a polyamide resin layer. And the tensile elongationat break of the base material layer in the MD direction and the TD direction ranges from 85% to 130%. The ratio of the tensile elongation at break in the MD direction of the base material layer to thetensile elongation at break in the TD direction is in the range of 1.0-1.4. The tensile breaking strength of the base material layer in both the MD direction and the TD direction is 250 MPa or more.