The method includes the steps of: preparing a single crystal SiC including an upper surface 10a and a lower surface 10b and provided with a micropipe 11 penetrating from the upper surface 10a to the lower surface 10b; forming a first seed layer 21 made of a metal material on the upper surface 10a of the single crystal SiC; and forming a first plated layer 31 on the first seed layer 21 so as to close an upper end of the micropipe 11, using an electroplating method.