A nitride semiconductor device, which includes a III-V Group nitride semiconductor layer being composed of a III Group element consisting of at least one of a group containing of gallium, aluminum, boron and indium and V Group element consisting of at least nitrogen among a group consisting of nitrogen, phosphorus and arsenic, including a first nitride semiconductor layer including the III-V Group nitride semiconductor layer being deposited on a substrate, a second nitride semiconductor layer including the III-V Group nitride semiconductor layer being deposited on the first nitride semiconductor and not containing aluminum and a control electrode making Schottky contact with the second nitride semiconductor layer wherein the second nitride semiconductor layer includes a film whose film forming temperature is lower than the first nitride semiconductor layer.