The inventive concept provides a substrate treating apparatus. The substrate treating apparatus includes a chamber having an inner space; a separation unit provided at the inner space and configured to be combined with the chamber to divide the inner space into a plurality of treating spaces and a transfer space; a plurality of support units provided at each of the plurality of treating spaces and configured to support a substrate; a plurality of gas supply units provided at each of the plurality of treating spaces and configured to supply a process gas to the substrate supported on the plurality of support units; and a transfer unit provided at the transfer space and configured to transfer the substrate between the plurality of treating spaces.