A method for using a vacuum apparatus that includes a vacuum chamber and a pump, the vacuum chamber housing an object, the pump reducing an internal pressure of the vacuum chamber, the method including: ventilating inside the vacuum chamber by introducing a gas into the vacuum chamber and discharging the gas from the vacuum chamber by causing the pump to reduce the internal pressure of the vacuum chamber. In the ventilating, a discharge rate at which molecules of the gas per unit volume are discharged is at least 3.3×10−5 mol/(s·L), and the temperature in the vacuum chamber is at least 15° C. and at most 80° C.