A semiconductor device includes a semiconductor substrate having an insulation layer and a semiconductor layer formed on the insulation layer; a channel area formed in the semiconductor layer; a gate electrode formed on the channel area; a source area formed in the semiconductor layer and having a depth not reaching the insulation layer; a drain area formed in the semiconductor layer adjacent to the source area with the channel area in between and having a depth reaching the insulation layer; a separation area disposed next to the source area opposite to the channel area and having a depth not reaching the insulation layer; a high-concentration body area formed in the semiconductor layer at lease in a surface layer thereof and between the first separation area and the second separation area; and a body contact disposed on the high-concentration body area.