A nitride semiconductor device includes first electrode interconnect layers and second electrode interconnect layers formed over a nitride semiconductor layer, a first insulating film formed on the first and second electrode interconnect layers and including first openings, first interconnect layers and second interconnect layers formed on the first insulating film and respectively connected to the first electrode interconnect layers and the second electrode interconnection layers through the first openings, a second insulating film formed on the first and second interconnect layers and including second openings, and a first pad layer and a second pad layer formed on the second insulating film and respectively connected to the first interconnect layers and the second interconnect layers through the second openings.