A battery pack includes at least two or more bare cells, a lead tab and an insulating member. Each of the bare cells has a first terminal portion. The lead tab is provided to the first terminal portion of the bare cell. The insulating member is interposed between the bare cell and the lead tab and is provided with an opening so that the bare cell and the lead tab are electrically connected to each other. In the battery pack, the insulating member includes two or more bare cell facing portions respectively corresponding to the bare cells, an extending portion that connects neighboring bare cell facing portions to each other, and guide portions respectively provided to the bare cell facing portions so as not to be arranged in one straight line.