PURPOSE: To obtain the waste disposal place having a large volume as compared with the site area, capable of being constructed at a low cost and without causing environmental deterioration by making the water level in a waste dumping space surrounded by the underground continuous wall extending to the impermeable layer slightly below the groundwater level.

CONSTITUTION: Waste 10 is dumped in the space 5 filled with water 6, and the water level 7 rises. Accordingly, the water in the space is pumped up by a pump provided, and the level is kept slightly below the groundwater level 8 outside. Since the water pressure in the space is lower than the outside water pressure, sewage in the space does not flow out to the outside. The force acting on the continuous wall when in operation is low, the outside and inside groundwater levels under construction are the same, and strong force is not exerted. Consequently, the continuous wall can be built at a low cost, a water stopping work at the bottom is dispensed with, and the dumping space can be dug close to the lowermost end of the continuous wall.