A battery system includes: a battery unit formed by electrically connected in series a plurality of cell groups each made up with a plurality of battery cells electrically connected in series; a plurality of sensing lines for detecting voltages of respective battery cells in the battery unit; an integrated circuit provided to each of the cell group, to which the sensing lines for detecting voltages of respective battery cells in the cell group are connected; a case having housed therein a substrate at which a plurality of integrated circuits provided for the cell groups respectively are mounted; noise protection capacitors disposed between input terminals of the plurality of sensing lines; and at least one protection element against static electricity which is connected between the input terminals and the case.
