According to one embodiment, a semiconductor device includes a base body including silicon carbide, a first semiconductor region including silicon carbide and a first element, and a second semiconductor region including silicon carbide and the first element. The first semiconductor region includes first and second intermediate regions. A first concentration of the first element in the first intermediate region satisfies a first or a second condition. In the first condition, the first concentration is lower than a second concentration of the first element in the second intermediate region. In the second condition, the first concentration is higher than a third concentration of a second element included in the first intermediate region, the second concentration is higher than a fourth concentration of the second element in the second intermediate region, and a difference between the first and third concentrations is smaller than a difference between the second and fourth concentrations.