A battery pack, comprising: a plurality of unit batteries wherein each unit battery comprises a battery main unit with a rectangular shape, and a positive-electrode pulled-out tab and a negative-electrode pulled-out tab pulled out from an end portion of the battery main unit; a board; and a holder member that is fixed to the board and includes pulled-out tab insertion holes into which the positive-electrode and negative-electrode pulled-out tabs (120, 130) of the plurality of the unit batteries are inserted, wherein the board includes pulled-out tab extraction holes provided so as to correspond to the pulled-out tab insertion holes of the holder member and into which the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs are inserted, and a thin-film electrode section (320a, 320b, 320c) that is provided on an outer surface of the board in areas where the pulled-out tabs (120, 130) are fixed to the board so as to function as a pulled-out tab connection section with the positive-electrode pulled-out tab and/or the negative-electrode pulled-out tab being fixed thereto, the unit batteries are stacked, characterized in that the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs of the unit batteries positioned at both ends of the direction in which the unit batteries are stacked are pulled to the surface on which the thin-film electrode section (320a, 320b, 320c) is provided around a side surface of the board, the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs are bent in the same direction, and one of the positive-electrode pulled-out tabs or the negative-electrode pulled-out tabs is connected to a pulled-out tab of an opposite polarity of an adjacent unit battery on the thin-film electrode section (320a, 320b, 320c), and the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs of the unit batteries that are not positioned at both ends of the direction in which the unit batteries are stacked are pulled out to the surface on which the thin-film electrode section (320a, 320b, 320c) is provided through the pulled-out tab extraction hole, bent in opposite directions, and fixed on the thin-film electrode section (320a, 320b, 320c). a plurality of unit batteries wherein each unit battery comprises a battery main unit with a rectangular shape, and a positive-electrode pulled-out tab and a negative-electrode pulled-out tab pulled out from an end portion of the battery main unit; a board; and a holder member that is fixed to the board and includes pulled-out tab insertion holes into which the positive-electrode and negative-electrode pulled-out tabs (120, 130) of the plurality of the unit batteries are inserted, wherein the board includes pulled-out tab extraction holes provided so as to correspond to the pulled-out tab insertion holes of the holder member and into which the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs are inserted, and a thin-film electrode section (320a, 320b, 320c) that is provided on an outer surface of the board in areas where the pulled-out tabs (120, 130) are fixed to the board so as to function as a pulled-out tab connection section with the positive-electrode pulled-out tab and/or the negative-electrode pulled-out tab being fixed thereto, the unit batteries are stacked, characterized in that the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs of the unit batteries positioned at both ends of the direction in which the unit batteries are stacked are pulled to the surface on which the thin-film electrode section (320a, 320b, 320c) is provided around a side surface of the board, the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs are bent in the same direction, and one of the positive-electrode pulled-out tabs or the negative-electrode pulled-out tabs is connected to a pulled-out tab of an opposite polarity of an adjacent unit battery on the thin-film electrode section (320a, 320b, 320c), and the positive-electrode pulled-out tabs and the negative-electrode pulled-out tabs of the unit batteries that are not positioned at both ends of the direction in which the unit batteries are stacked are pulled out to the surface on which the thin-film electrode section (320a, 320b, 320c) is provided through the pulled-out tab extraction hole, bent in opposite directions, and fixed on the thin-film electrode section (320a, 320b, 320c).