In the semiconductor device of the present invention, an active region is formed in an upper surface of a semiconductor substrate, and is surrounded by a trench filled with an oxide. A through-hole electrode electrically connected to the active region extends from the upper surface of the semiconductor substrate to a lower surface thereof. A bottom end of the through-hole electrode juts out of an insulating film covering the lower surface of the semiconductor substrate. Accordingly, a jutting portion of the through-hole electrode is embedded in the bonding material when the semiconductor device is mounted on a mounting board, and thus the connection reliability therebetween is improved.