PURPOSE: To obtain a device excellent in economy, and requiring no fuel cost as well as to eliminate pollution of the earth caused by energy, by obtaining pollution-free energy in place of energy used at present.

CONSTITUTION: Liquid/air containers 1 provided with rods with rollers are attached to a liquid/air hole belt 8 in liquid in the container, and liquid/air blowing machine and a liquid/air stopping tool are attached to shafts 4, and liquid is sucked and discharged to the liquid/air container on one side of the belt, and air is sucked and discharged to the other side, and power is obtained by the buoyancy.