A manufacturing method of a semiconductor device includes: forming an electric metal layer by depositing metal as art electrode material on an inside of an opening of an insulating layer on a surface of an SiC semiconductor substrate (4); widening a gap between an inner wall surface in an opening formed in the insulating layer and the electrode metal layer by etching the insulating layer after the electrode metal layer is formed; and forming, an ohmic contact between the electrode metal layer and the SiC semiconductor substrate by heating the SiC semiconductor substrate and the metal electrode layer after the insulating layer is etched.