DEAERATOR

A degassing apparatus capable of preventing cross-contamination is provided. A degassing apparatus 1 includes degassing modules 10, 20, and 30 each having a tube unit 12 that is a gas permeable membrane separating a fluid circulation space S1 and a reduced-pressure space S2 from each other, vacuum piping 40 communicatively connected to the reduced-pressure spaces S2, a discharge device 50 that discharges gas in the reduced-pressure spaces S2 through the vacuum piping 40, atmospheric release piping 60 communicatively connected to the reduced-pressure spaces S2, an atmospheric release valve 70 capable of introducing atmosphere into the reduced-pressure spaces S2 through the atmospheric release piping 60, and a control unit 80 that controls the operation of the discharge device 50 and the atmospheric release valve 70. The control unit 80 performs control to close the atmospheric release valve 70 to perform a process of discharging gas in the reduced-pressure spaces S2 by the discharge device 50 when a degassing process is being performed, and performs control to open the atmospheric release valve 70 to open the reduced-pressure spaces S2 to the atmosphere at once after the degassing process is finished.