There is provided a thermal treatment method of a silicon wafer. The method includes the successive steps of: (a) terminating silicon atoms existing on an active surface of the silicon wafer with hydrogen, wherein the active surface is mirror-polished, and a semiconductor device is to be formed on the active surface; (b) terminating the silicon atoms existing on the active surface of the silicon wafer with fluorine; (c) rapidly heating the silicon wafer to a first temperature under an inert gas atmosphere or a reducing gas atmosphere, wherein the first temperature is in a range of 1300° C. to 1400° C.; (d) holding the silicon wafer at the first temperature for a certain time; and (e) rapidly cooling the silicon wafer.