A silicon carbide semiconductor device includes a semiconductor substrate, a first semiconductor layer, a second semiconductor layer, a first semiconductor region, and a gate electrode. Protons are implanted in a first region spanning a predetermined distance from a surface of the semiconductor substrate facing toward the first semiconductor layer, in a second region spanning a predetermined distance from a surface of the first semiconductor layer on the second side of the first semiconductor layer facing toward the semiconductor substrate, in a third region spanning a predetermined distance from a surface of the first semiconductor layer on the first side of the first semiconductor layer facing toward the second semiconductor layer, and in a fourth region spanning a predetermined distance from a surface of the second semiconductor layer on the second side of the second semiconductor layer facing toward the first semiconductor layer.