The semiconductor device includes a GaN-based layered body having an opening and including an n-type drift layer and a p-type layer located on the n-type drift layer, a regrown layer including a channel and located so as to cover the opening, and a gate electrode located on the regrown layer and formed along the regrown layer, wherein the opening reaches the n-type drift layer, and an edge of the gate electrode is not located outside a region of the p-type layer when viewed in plan.