A semiconductor device includes a package substrate having a front surface and a backside surface; an electrode pad formed on the front surface; an outer connection pad formed on the backside surface and electrically connected to the electrode pad; a semiconductor chip mounted on the front surface and having an electrode electrically connected to the electrode pad; a sealing resin layer having a through hole formed with a die-molding and reaching the electrode pad for sealing the semiconductor chip; and a through electrode filled in the through hole with a conductive material and having one end portion electrically connected to the electrode pad and the other end portion exposed from the sealing resin layer.