According to the present invention, a semiconductor device includes a semiconductor layer, a source electrode provided in the semiconductor layer, a drain electrode provided in the semiconductor layer and disposed away from the source electrode, a first gate electrode provided between the source electrode and the drain electrode and a second gate electrode provided between the source electrode and the drain electrode, the second gate electrode having at least a part thereof located closer to the drain electrode than the first gate electrode. The semiconductor layer includes a first facing part that is a part facing the first gate electrode; and a second facing part that is a part facing the second gate electrode. The first facing part does not conduct when a first gate voltage is 0 V or less. The second facing part does not conduct when a second gate voltage is 0 V or less.