To provide a battery pack in which unevenness of the current path resistance of the plural protection circuits are suppressed.

The battery pack comprises two sets of secondary batteries housed in a case and each set of the secondary batteries has an outside terminal corresponding to the positive electrode and the negative electrode, and each outside terminal is electrically connected to the positive electrode and the negative electrode of the secondary batteries which are opposed to each other independently. The battery pack comprises two chips which are made by molding two FET's in the same mold, and the secondary batteries comprise a protection circuit respectively and the two protection circuits use the FET in the same mold one for each separately.