Embodiments of the inventive concept relate to an apparatus for supporting a substrate and a method for treating a substrate. The substrate support apparatus includes a substrate support member including a support plate having an upper surface that supports a substrate, and a heating member provided in the support plate to heat the substrate, wherein an area of the support plate has a buffer area, in which a buffer space for restricting a heat transfer rate of heat provided from the heating member to the upper surface is formed. The buffer space insulates a central area and a peripheral area, thereby maximizing a temperature difference between the central area and the peripheral area.