A silicon single-crystal wafer having a diameter of 6 inches or larger and improved in the dielectric breakdown strength of oxide film especially in a peripheral part thereof is provided to thereby heighten the yield of device chips produced per wafer. This wafer has no crystal defects with regard to the dielectric breakdown strength of oxide film in its peripheral region which extends from the circumference and accounts for up to 50% of the total area, in particular which extends from the circumference to a circle 30 mm apart from the circumference. A process for producing a silicon single crystal for easily producing, by the Czochralski method, a silicon single-crystal wafer improved in the dielectric breakdown strength of oxide film especially in a peripheral part thereof without considerably lowering the production efficiency is provided. In this process, the silicon single crystal which is being grown by the Czochralski method is pulled at a rate which is 80 to 60% of the critical pull rate inherent in the pulling apparatus.