A semiconductor device which is compact and thin in size, low in resistance of a current path and parasitic inductance and excellent in reliability is provided. This semiconductor device comprises a semiconductor substrate, a first main electrode which is formed on a front surface of the semiconductor substrate, a second main electrode which is formed on a rear surface of the semiconductor substrate, and a conducting portion which is formed in a direction to pierce through the semiconductor substrate, wherein the second main electrode is extracted to the front surface of the semiconductor substrate via the conducting portion. And, the conducting portion is a through via which has a through hole formed through the semiconductor substrate in its thickness direction and a conductive portion which is formed in the through hole and connected to the second main electrode.