A method of exhausting a gas in a chamber of a load-lock system having a first valve defining an opening for supplying a gas and a second valve defining an opening for conveyance of an article. The method includes a gas supplying step for supplying a gas heated by a heater into the chamber through the first valve, while the first valve and the second valve are kept open, a conveying step for conveying the article into the chamber while the second valve is kept open, and an exhausting step to be carried out after the gas supplying step and the conveying step are executed and the first and second valves are closed, to exhaust the gas inside the chamber while the first valve and the second valve are kept closed.