A lead-acid battery comprising: elements each having positive electrode plates and negative electrode plates alternately layered with a separator provided in between and comprising a lug portion; straps connected to the lug portions of the elements; and a plurality of cell chambers accommodating the respective elements and the respective straps separately, wherein a direction in which the positive electrode plates and the negative electrode plates are layered is defined as a first direction, a direction in which the lug portions and the straps are connected to each other is defined as a second direction, and a direction orthogonal to the first direction and the second direction is defined as a third direction, the straps each include: a base portion including a connection region connected with the lug portion; a tab portion having at least a part positioned in the third direction with respect to the base portion; and an inter cell connection portion protruding in the first direction from the tab portion and electrically connecting the elements accommodated in adjacent ones of the cell chambers, and a second cross-sectional area is larger than a first cross-sectional area, where the first cross-sectional area is a minimum cross-sectional area of the inter cell connection portion in a plane orthogonal to the first direction, and the second cross sectional area is a minimum cross-sectional area of the strap in a plane dividing the strap into one side corresponding to the connection region and another side corresponding to the inter cell connection portion. elements each having positive electrode plates and negative electrode plates alternately layered with a separator provided in between and comprising a lug portion; straps connected to the lug portions of the elements; and a plurality of cell chambers accommodating the respective elements and the respective straps separately, wherein a direction in which the positive electrode plates and the negative electrode plates are layered is defined as a first direction, a direction in which the lug portions and the straps are connected to each other is defined as a second direction, and a direction orthogonal to the first direction and the second direction is defined as a third direction, the straps each include: a base portion including a connection region connected with the lug portion; a tab portion having at least a part positioned in the third direction with respect to the base portion; and an inter cell connection portion protruding in the first direction from the tab portion and electrically connecting the elements accommodated in adjacent ones of the cell chambers, and a base portion including a connection region connected with the lug portion; a tab portion having at least a part positioned in the third direction with respect to the base portion; and an inter cell connection portion protruding in the first direction from the tab portion and electrically connecting the elements accommodated in adjacent ones of the cell chambers, and a second cross-sectional area is larger than a first cross-sectional area, where the first cross-sectional area is a minimum cross-sectional area of the inter cell connection portion in a plane orthogonal to the first direction, and the second cross sectional area is a minimum cross-sectional area of the strap in a plane dividing the strap into one side corresponding to the connection region and another side corresponding to the inter cell connection portion.