A semiconductor device in which moisture penetration into the package interior is suppressed, comprising a rewiring layer formed by plating, with improved reliability of electrical characteristics. On the main surface of a semiconductor chip comprising circuit elements and formed on a wafer, a passivation film opposing the circuit elements is formed, so as to expose a first region of the main surface along the edges of the main surface. An insulating film, which extends over the main surface and along the side faces of this passivation film and onto the main surface of the semiconductor chip, is formed such that there remains a second region within the first region, along the edges of the main surface. A sealing layer covering the insulating film is then formed on the second region.