A semiconductor device comprises: a base; a semiconductor chip provided on the base which includes a first main surface 20a on which a plurality of electrode pads is provided, a surface protecting film provided on the first main surface, a second main surface which opposes the first main surface, and a plurality of side surfaces between the surface of the surface protecting film and the second main surface; an insulating extension portion formed so as to surround the side surfaces of the semiconductor chip; a plurality of wiring patterns electrically connected to the electrode pads, respectively and extended from the electrode pads to the surface of the extension portion; a sealing portion formed on the wiring patterns such that a part of each of the wiring patterns is exposed; and a plurality of external terminals provided on the wiring patterns in a region including the upper side of the extension portion.