A battery pack comprising: a plurality of batteries including respective electrode terminals (1x, 1y) disposed in face-to-face relation; and a lead plate connecting each of the plurality of batteries, the lead plate including a turnback part and fixed pieces connected to the electrode terminals (1x, 1y), wherein the lead plate further includes: a flat part at each of ends of the turnback part; and a connective arm connecting the flat part and at least one of the fixed pieces, the connective arm having a narrower width than a width of the at least one of the fixed pieces, the lead plate including: a first flat part that connects as one of the flat parts with one of the ends of the turnback part; and a second flat part that connects as another of the flat parts with another of the ends of the turnback part, each of sides of the first flat part is connected to a first fixed piece of the fixed pieces via the connective arm, and each of sides of the second flat part is connected to a second fixed piece of the fixed pieces without the use of the connective arm, the connective arm including: a first end connecting with the first fixed piece; and a second end connecting with the first flat part, and the second end connecting with the first flat part is distant from the turnback part compared with the first end, with the connective arm paralleling a side of the flat part; the turnback part includes a bending part, the bending part is provided at a boundary between the turnback part and the first flat part, and the bending part includes any one of a through hole provided in the turnback part, a side notch where the turnback part has a narrowed width, and a thinned part that is a thinned part of the turnback part. a plurality of batteries including respective electrode terminals (1x, 1y) disposed in face-to-face relation; and a lead plate connecting each of the plurality of batteries, the lead plate including a turnback part and fixed pieces connected to the electrode terminals (1x, 1y), wherein the lead plate further includes: a flat part at each of ends of the turnback part; and a connective arm connecting the flat part and at least one of the fixed pieces, the connective arm having a narrower width than a width of the at least one of the fixed pieces, a flat part at each of ends of the turnback part; and a connective arm connecting the flat part and at least one of the fixed pieces, the connective arm having a narrower width than a width of the at least one of the fixed pieces, the lead plate including: a first flat part that connects as one of the flat parts with one of the ends of the turnback part; and a second flat part that connects as another of the flat parts with another of the ends of the turnback part, a first flat part that connects as one of the flat parts with one of the ends of the turnback part; and a second flat part that connects as another of the flat parts with another of the ends of the turnback part, each of sides of the first flat part is connected to a first fixed piece of the fixed pieces via the connective arm, and each of sides of the second flat part is connected to a second fixed piece of the fixed pieces without the use of the connective arm, the connective arm including: a first end connecting with the first fixed piece; and a second end connecting with the first flat part, and a first end connecting with the first fixed piece; and a second end connecting with the first flat part, and the second end connecting with the first flat part is distant from the turnback part compared with the first end, with the connective arm paralleling a side of the flat part; the turnback part includes a bending part, the bending part is provided at a boundary between the turnback part and the first flat part, and the bending part includes any one of a through hole provided in the turnback part, a side notch where the turnback part has a narrowed width, and a thinned part that is a thinned part of the turnback part.