A substrate processing apparatus includes a chamber providing a space in which a substrate is processed, a first substrate support within the chamber and configured to support the substrate when the substrate is loaded into chamber, a second substrate support within the chamber and configured to support the substrate in a height greater than the height in which the first substrate supports the substrate, a first supply port through which a supercritical fluid is supplied to a first space under the substrate of a chamber space, a second supply port through which the supercritical fluid is supplied to a second space above the substrate of the chamber space, and an exhaust port through which the supercritical fluid is exhausted from the chamber.