A suction discharge unit 11 of a suction discharge device 10 includes a first unit 21 and a second unit 22. The second unit 22 controls the pressure inside the first unit 21. The first unit 21 includes a storage chamber 41 and a water sealing chamber 42. The water sealing chamber 42 includes a first chamber 42a, which communicates with the storage chamber 41, and a second chamber 42b, which is sealed from the first chamber 42a by sealing water 36. A negative pressure control unit 50 is disposed in the second chamber 42b. The negative pressure control unit 50 includes a liquid retaining part that retains a liquid 54, a control member 52 that includes control holes 52X, and a support tube 53 that supports the control member 52. The negative pressure control unit 50 controls the pressure of the first chamber 42a by causing gas to flow from the second chamber 42b into the first chamber 42a via the control holes 52X and the liquid 54 on the basis of the pressure of the second chamber 42b and the pressure of the first chamber 42a.
