The inventive concept provides a substrate treating apparatus. The substrate treating apparatus includes a chamber having a treating space therein; a supply line having a first open/close valve installed thereon and configured to supply a treating fluid to the treating space; a heater installed on the supply line and configured to heat the treating fluid; an exhaust line having a second open/close valve installed thereon and configured to exhaust the treating space; and, a controller configured to control the first open/close value and the second open/close valve such that the treating fluid heated is supplied to and exhausted from the treating space before a treating process is performed on a substrate in the treating space.