PURPOSE: To actuate a vacuum valve to which a breather pipe is connected by forming an air reservoir inside by way of providing a cap excellent in airtightness and watertightness in a layer of favourable permeability and opening the head end of the breather pipe to this air reservoir.

CONSTITUTION: A cap 14 excellent in airtightness and watertightness is provided in a permeable layer 21 of a container 13 by way of opening its lower side, and by forming an air reservoir 17, air in the air reservoir 17 becomes atmospheric pressure through the permeable layer 21. A head end 18 of a breather basin 12 is opened in the air reservoir 17. Waste water discharged from a waste water discharging point flows in a waste water basin part 6 from a waste water inflow pipe 7 and is temporarily reserved, and when it becomes higher than an upper level, a detection pipe 8 detects it and a vacuum valve 4 is opened. Thereby, the inside of a waste water suction pipe 9 is communicated to a vacuum waste water pipe 10 and the inside of the waste water suction pipe becomes vacuum, and waste water in the waste water basin part 6 is drawn and automatically flows to a vacuum sewage main pipe. When it becomes lower than a lower level and air enters from the lower end of the waste water suction pipe 9, pressure change is detected and the vacuum valve is closed.