A battery module 8 containing parallel blocks 9 connected to a protection circuit via a lead plate 2, wherein the parallel blocks 9 are welded to both sides of the lead plate without bending the lead plate 2 into a U shape. Thus it is possible to reduce the length of the lead plate 2 and suppress a voltage drop on the lead plate 2. Further, since the lead plate 2 is not bent into a U shape, the assembling accuracy of the battery module is improved and the battery module is easily packaged with a small size.