A SiC epitaxial wafer manufacturing method comprising: manufacturing a SiC epitaxial wafer including a SiC epitaxial layer on a surface of a SiC single crystal wafer while supplying a raw material gas into a chamber using a SiC epitaxial wafer manufacturing apparatus; and manufacturing a subsequent SiC epitaxial wafer after measuring a surface density of triangular defects having a material piece of an internal member, which is a shielding plate, of the chamber as a starting point on the SiC epitaxial layer of the previously manufactured SiC epitaxial wafer, wherein the starting point is in the front of the apex of the triangular defect in a direction distant from the opposite side; identifying the density of the triangular defect by measuring the starting point by shifting a position of focus in an optical image from a surface of the SiC epitaxial layer toward an interface between the SiC epitaxial layer and the SiC single crystal substrate and replacing the shielding plate of the chamber according to the measurement result of the surface density, wherein the SiC epitaxial wafer manufacturing apparatus includes a susceptor that includes a wafer placement unit on which the wafer is placed, a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate, and the shielding plate that is disposed to be close to a lower surface of the top plate to such an extent that a deposit is prevented from being attached to the lower surface of the top plate and dust emitted from the lower surface of the top plate is received, and the shielding plate is configured to be detachable and is formed of a graphite substrate covered with a silicon carbide film or a pyrolytic carbon film, a thickness of the shielding plate is within the range of 2 mm to 6 mm, and a film thickness of the silicon carbide film or the pyrolytic carbon film is within the range of 20 μm to 100 μm. manufacturing a SiC epitaxial wafer including a SiC epitaxial layer on a surface of a SiC single crystal wafer while supplying a raw material gas into a chamber using a SiC epitaxial wafer manufacturing apparatus; and manufacturing a subsequent SiC epitaxial wafer after measuring a surface density of triangular defects having a material piece of an internal member, which is a shielding plate, of the chamber as a starting point on the SiC epitaxial layer of the previously manufactured SiC epitaxial wafer, wherein the starting point is in the front of the apex of the triangular defect in a direction distant from the opposite side; identifying the density of the triangular defect by measuring the starting point by shifting a position of focus in an optical image from a surface of the SiC epitaxial layer toward an interface between the SiC epitaxial layer and the SiC single crystal substrate and replacing the shielding plate of the chamber according to the measurement result of the surface density, wherein the SiC epitaxial wafer manufacturing apparatus includes a susceptor that includes a wafer placement unit on which the wafer is placed, a top plate that is disposed to face an upper surface of the susceptor so that a reaction space is formed between the susceptor and the top plate, and the shielding plate that is disposed to be close to a lower surface of the top plate to such an extent that a deposit is prevented from being attached to the lower surface of the top plate and dust emitted from the lower surface of the top plate is received, and the shielding plate is configured to be detachable and is formed of a graphite substrate covered with a silicon carbide film or a pyrolytic carbon film, a thickness of the shielding plate is within the range of 2 mm to 6 mm, and a film thickness of the silicon carbide film or the pyrolytic carbon film is within the range of 20 μm to 100 μm.