To stably convey sewage by applying the vacuum pressure of a vacuum sewer pipe to an air chamber, and applying the atmospheric pressure to it with a controller detecting that the sewage level of a sewage sump reaches a set level.

When the sewage level of a sewage sump rises and reaches a set level, a controller 33 introduces the atmospheric pressure to an air chamber 30 to increase the air pressure of the air chamber 30. When the vacuum suction force applied to a piston 18 is decreased to below the spring force of a spring 26, the piston 18 is moved to the valve opening direction, and a valve element 13 is opened. When a vacuum valve 10 is opened, sewage flows into a vacuum sewer pipe 1, the vacuum valve 10 is further opened to suck sewage and air. The air conveys the sewage through the sewer pipe 1. When the suction of sewage is completed and the sewage level is lowered, no air is fed to the air chamber 30. As the degree of vacuum of the sewer pipe 1 is recovered, the vacuum valve 10 is closed. The sewage can be stably conveyed.