A semiconductor device includes a semiconductor substrate having a main surface; a first coil formed on the main surface; a first insulating film formed over the first coil and having a first main surface; a second insulating film formed on the first main surface of the first insulating film and having a second main surface; and a second coil formed on the second main surface of the second insulating film, wherein the first main surface of the first insulating film has a first area on which the second insulating film is formed, and has a second area without the first area in a plan view, and wherein the second insulating film is surrounded with the second area in the plane view.