A semiconductor device including a first conduction type semiconductor layer; a second conduction type element forming region formed above the first conduction type semiconductor layer and formed with at least one semiconductor element formed on a surface region of the second conduction type element forming region; a first conduction type element-isolation region insulating and segregating the second conduction type element forming region from the exterior; and a second conduction type buried region formed at the interface of the first conduction type semiconductor layer and the second conduction type element forming region, formed separated from the first conduction type element-isolation region. In the semiconductor device a second conduction type high concentration region is buried in the surface of the second conduction type element forming region and formed to surround the semiconductor element and separated from the first conduction type element-isolation region.