A semiconductor device includes a semiconductor chip having a first main surface having an electrode pad in an exposed state, and an interlayer insulation layer formed on the first main surface so that the electrode pad is partially exposed; a re-distribution wiring layer including a wiring pattern having a linear portion having one end portion electrically connected to the electrode pad and extending from the electrode pad, and a post electrode mounting portion with a recessed polygonal shape and connected to the other end portion of the linear portion; a post electrode formed on the post electrode mounting portion and having a bottom surface with a contour crossing an upper contour of the post electrode mounting portion at more than two points; a sealing portion disposed so that a top of the post electrode is exposed; and an outer terminal formed on the top of the post electrode.