According to the embodiments, a semiconductor device using SiC and having a high breakdown voltage, a low on-resistance, and excellent reliability is provided. The semiconductor device includes a silicon carbide substrate having first and second main surfaces; a first silicon carbide layer of a first conductive type provided on the first main surface of the silicon carbide substrate; first silicon carbide regions of a second conductive type formed on a surface of the first silicon carbide layer; second silicon carbide regions of the first conductive type formed on respective surfaces of the first silicon carbide regions; third silicon carbide regions of the second conductive type formed on the respective surfaces of the first silicon carbide regions; a fourth silicon carbide region of the second conductive type formed between the facing first silicon carbide regions with the first silicon carbide layer therebetween; a gate insulating film formed continuously on surfaces of the first silicon carbide regions, the first silicon carbide layer, and the fourth silicon carbide region; a gate electrode formed on the gate insulating film; an interlayer insulating film which covers the gate electrode; a first electrode which is electrically connected to the second silicon carbide regions and the third silicon carbide regions; and a second electrode formed on the second main surface of the silicon carbide substrate.