Three support members made of silicon carbide are provided fixedly on an inner periphery of the support ring. The support members are inclined at an angle in the range of 15 to 30 degrees with respect to a horizontal plane. With an outer peripheral edge of a semiconductor wafer supported by the three support members, a heating treatment is performed by irradiating the semiconductor wafer with halogen light from halogen lamps. Silicon carbide absorbs the halogen light better than quartz. The support members support the outer peripheral edge of the semiconductor wafer in point contacting relationship, so that the contact between a holder and the semiconductor wafer is minimized. This minimizes the disorder of the temperature distribution of the semiconductor wafer due to the support members to achieve the uniform heating of the semiconductor wafer.