To vertically carry out an excavated muck from the great depth of the ground by a device having a simple constitution as well as the use of natural energy from buoyancy.

The excavated muck 20 consisting of earth and sand, rock or the like resulted from excavatgion work or the like and water 22 are led to a freezing compartment 18, and after both of them are once put into a container which is not illustrated and is mixed, it is cooled and is solidified. It is favorable that ground water is used as mixing water. A cooling solid 24 is moved to an air-tight compartment 16, and after it is taken out from the container, it is conveyed into a shaft filled with a liquid 14. Since buoyancy acts on the cooling solid 24 by the density difference between the cooling solid and the circumferential fluid 14, the cooling solid 24 is vertically raised inside of the shaft 12, and the excavated muck 20 conveyed as the cooling solid 24 can be carried out from the inside of an underground tunnel by taking it out from the shaft 12 on the ground.