A semiconductor device includes: a laminated body including a channel layer that is configured of a compound semiconductor; and at least one gate electrode that is provided on a top surface side of the laminated body, wherein the laminated body includes a first low-resistance region that is provided on the top surface side of the laminated body, the first low-resistance region facing the at least one gate electrode, and a second low-resistance region that is provided externally of the first low resistance region on the top surface side of the laminated body, the second low-resistance region being continuous with the first low-resistance region.