A silicon carbide substrate capable of reducing on-resistance and improving yield of semiconductor devices is made of single-crystal silicon carbide, and sulfur atoms are present in one main surface at a ratio of not less than 60×1010 atoms/cm2 and not more than 2000×1010 atoms/cm2, and oxygen atoms are present in the one main surface at a ratio of not less than 3 at % and not more than 30 at %.