The objective of the invention is to overcome a problem that an adhesion part between a heat sink and a substrate peels off because the heat sink configured to a semiconductor chip and the substrate expands or contracts along with heat. A semiconductor device includes a substrate whose surface is made of an insulation material, a semiconductor chip flip-chip connected on the substrate, and a heat sink bonded to the semiconductor chip via a thermal interface material and fixed to the substrate outside the semiconductor chip, wherein the heat sink has a protrusion part protruding toward the substrate and bonded to the substrate via a conductive resin between a part bonded to semiconductor chip and a part fixed to the substrate and the heat sink has a stress absorbing part. According to the semiconductor device, the protrusion part of the heat sink is prevented from being peeled off due to heat expansion or heat contraction from the substrate at the part where the protrusion part of the heat sink is bonded to the substrate.