A semiconductor device includes a semiconductor substrate, a buried insulating film, a first conductive film, an insulating layer, a first contact and a second contact. The semiconductor substrate includes a first semiconductor region having a first conductive type and a second semiconductor region having a second conductive type. The buried insulating film surrounds the second semiconductor region in plan view. The first conductive film directly contacts with the first and second semiconductor regions. The first and second contacts overlap with the second semiconductor region in plan view and reach the first conductive film. The first contact is adjacent to the second contact along a first side of the second semiconductor region in plan view. In a direction along the first side, a first distance between the second semiconductor region and the buried insulating film is greater than a second distance between the first contact and the second contact.