Packaging performance of a semiconductor device is improved. A semiconductor device has a package substrate having a base material formed of resin; a semiconductor chip mounted on a main surface of the package substrate; a tape substrates being stacked on the package substrate in several stages, and electrically connected to a substrate at a lower stage via a plurality of solder balls; a second-stage chip, third-stage chip, and fourth-stage chip mounted on the tape substrates at respective stages; and a plurality of solder balls provided on a back surface of the package substrate; wherein a sealing body, which resin-seals the semiconductor chip and is formed by resin molding, is formed on a main surface of a package substrate disposed at the lowest stage, and the sealing body is disposed between the package substrate at the lowest stage and the tape substrate stacked thereon.