An external packaging material for a laminated battery, which is one of two external packaging materials constituting a battery case accommodating a battery element, and is configured by a stainless steel sheet provided with a resin layer, the battery case being formed by fusing together the resin layers in a state in which tabs connected to the battery element are disposed between the two external packaging materials, characterized by a stepped portion conforming to a cross-sectional shape of each of the tabs at a position where the tab is inserted between the two external packaging materials is formed in advance before the tab is inserted, wherein the tab has, at a position where the tab is inserted between the external packaging materials, first tab end surfaces extending along a width direction of the tab, first tab side surfaces extending along a thickness direction of the tab from end portions of the first tab end surfaces, second tab end surfaces extending along the width direction of the tab from end portions of the first tab side surfaces, and second tab side surfaces extending along the thickness direction of the tab from end portions of the second tab end surfaces, and the stepped portion is provided with: a first step end surface portion extending along the width direction of the tab so as to correspond to each of the first tab end surfaces when the stepped portion is placed on the tab; a first step side surface portion extending along the thickness direction of the tab from an end of the first step end surface portion so as to correspond to each of the first tab side surfaces when the stepped portion is placed on the tab; and a connection portion connecting an end of the first step side surface portion and an end of a joining portion extending along the width direction of the tab from a position outside the second tab side surface following the width direction of the tab, which is a position set apart, along the width direction and thickness direction of the tab, from an end of the first step side surface portion, when the stepped portion is placed on the tab, and wherein the connection portion is provided with: a second step end surface portion extending along the width direction of the tab from the end of the first step side surface portion so as to correspond to each of the second tab end surfaces when the stepped portion is placed on the tab; and a tilted portion constituted by a tilted surface connecting an end of the second step end surface portion and an end of the joining portion. a first step end surface portion extending along the width direction of the tab so as to correspond to each of the first tab end surfaces when the stepped portion is placed on the tab; a first step side surface portion extending along the thickness direction of the tab from an end of the first step end surface portion so as to correspond to each of the first tab side surfaces when the stepped portion is placed on the tab; and a connection portion connecting an end of the first step side surface portion and an end of a joining portion extending along the width direction of the tab from a position outside the second tab side surface following the width direction of the tab, which is a position set apart, along the width direction and thickness direction of the tab, from an end of the first step side surface portion, when the stepped portion is placed on the tab, and wherein the connection portion is provided with: a second step end surface portion extending along the width direction of the tab from the end of the first step side surface portion so as to correspond to each of the second tab end surfaces when the stepped portion is placed on the tab; and a tilted portion constituted by a tilted surface connecting an end of the second step end surface portion and an end of the joining portion. a second step end surface portion extending along the width direction of the tab from the end of the first step side surface portion so as to correspond to each of the second tab end surfaces when the stepped portion is placed on the tab; and a tilted portion constituted by a tilted surface connecting an end of the second step end surface portion and an end of the joining portion.