A semiconductor device includes a substrate, a semiconductor chip, a conductive member and an external electrode. A penetrating hole is formed in the substrate, the penetrating hole having an internal wall surface, the internal wall surface having a protrusion formed of a material constituting the substrate. The semiconductor chip has an electrode. The conductive member is formed over a particular region including the penetrating hole on one side of the substrate, and is electrically connected to the electrode of the semiconductor chip. The external electrode is provided through the penetrating hole, electrically connected to the conductive member, and projects from the other side of the substrate.