A silicon single crystal is produced by the CZ process by setting a hydrogen partial pressure in an inert atmosphere within a growing apparatus to 40 Pa or more but 400 Pa or less, and by growing a trunk part of the single crystal as a defect-free area free from the Grown-in defects. Therefore, a wafer the whole surface of which is composed of the defect-free area free from the Grown-in defects and which can sufficiently and uniformly form BMD can be easily produced. Such a wafer can be extensively used, since it can significantly reduce generation of characteristic defectives of integrated circuits to be formed thereon and contribute for improving the production yield as a substrate responding to the demand for further miniaturization and higher density of the circuits.