In a semiconductor device in which a plurality of semiconductor chips are stacked, performance is enhanced without deteriorating productivity. The semiconductor device has a plurality of elements, an interlayer insulating film, a pad, and a bump electrode electrically connected with the pad sequentially formed on a main surface of a silicon substrate and has a back-surface electrode formed on a back surface of the silicon substrate and electrically connected with the bump electrode. The bump electrode has a protruding portion penetrating through the pad and protruding toward the silicon substrate side. The back-surface electrode is formed so as to reach the protruding portion of the bump electrode from the back surface side of the silicon substrate toward the main surface side and to cover the inside of a back-surface electrode hole portion which does not reach the pad, so that the back-surface electrode is electrically connected with the bump electrode.