A precleaning apparatus includes a chamber having an internal space in which a substrate is cleaned, a substrate support disposed in the chamber and configured to support the substrate, a plasma generation unit disposed in the chamber and configured to generate plasma gas, a heating unit configured to heat the substrate on the substrate support, a cleaning gas supply unit configured to supply gas for oxide etching to the internal space of the chamber, and a hydrogen gas supply unit configured to supply hydrogen gas to the internal space of the chamber.