Reliability of a semiconductor device is improved. The semiconductor device PKG1 includes a wiring substrate SUB1, a semiconductor chip CHP1 and a capacitor CDC mounted on the upper surface 2t of the wiring substrate SUB1, and a lid LD formed of a metallic plate covering the semiconductor chip CHP1 and the wiring substrate SUB1. The semiconductor chip CHP1 is bonded to the lid LD via a conductive adhesive layer, and the capacitor CDC, which is thicker than the thickness of the semiconductor chip CHP1, is disposed in the cut off portion 4d1 provided in the lid LD, and is exposed from the lid LD.