To prevent a defect from becoming a passage of a leakage current and improve a breakdown voltage of a semiconductor element by filling a through-hole with a substance which does not generate new defects.

A Schottky diode 10 is provided with an n+ type single-crystal silicon carbide substrate 12 and an n-type epitaxial silicon carbide layer 14, while through-holes (micropipes) 16 exist in the substrate 12 and the epitaxial silicon carbide layer 14. Wall surfaces of the through-holes 16 are covered with an insulation layer 18 formed by the thermal oxidization of the substrate 12 and the silicon carbide layer 14, while the through-holes 16 are filled with a thermal stress relaxing substance 20. The thermal stress relaxing substance 20 is provided with insulation properties and a polycrystalline or an amorphous structure of superior stress-relaxing properties by slippage in an interface between crystal grains, or has a structure which does not exist in a precise crystal arrangement having small density.