A wafer supporting unit (10) includes a base (12) and a thermally conductive member (14). The base is formed by nickel material. The thermally conductive member is formed in the shape of a lamina, includes silicone rubber (16) serving as the main material, and Ag fine powder (18) is blended with the silicone rubber. The Ag fine powder is blended with high density in part of the thermally conductive member, and a plurality of pillar-shaped regions (20) is formed with one end facing the bottom, and with the other end facing the top. The wafer supporting unit does not produce curvature in a wafer, and provides efficient cooling of the wafer, and does not cause heat degradation in a thermally conductive member prepared on the rear side of the wafer during processing.