A silicon carbide semiconductor device includes: an element isolation layer and an electric field relaxation layer. The element isolation layer is arranged, from the surface of a base region to be deeper than the base region, between a main cell region and a sense cell region, and isolates the main cell region from the sense cell region. The electric field relaxation layer is arranged from a bottom of the base region to be deeper than the element isolation layer. The electric field relaxation layer is divided into a main cell region portion and a sense cell region portion. At least a part of the element isolation layer is arranged inside of a division portion of the electric field relaxation layer.