A semiconductor device according to an embodiment includes first electrode; second electrode; silicon carbide layer between the first electrode and the second electrode, the silicon carbide layer having first and second plane, the silicon carbide layer including first silicon carbide region of first-conductivity-type, second silicon carbide region and third silicon carbide region between the first silicon carbide region and the first plane, fourth silicon carbide region between the second silicon carbide region and the first plane, the fourth silicon carbide region contacting the first electrode, fifth silicon carbide region between the second silicon carbide region and the third silicon carbide region, the fifth silicon carbide region having a higher first-conductivity-type impurity concentration than the first silicon carbide region, sixth silicon carbide region between the fifth silicon carbide region and the first plane, the sixth silicon carbide region contacting the first electrode; gate electrode facing the second silicon carbide region.