PURPOSE: To separate and collect sand of less impurities from earth, sand or crushed stone by providing a vibrator on the side upper than a conveying surface in such a way as to apply vibrations directly to the sand on side conveying surface without applying the same to a belt.

CONSTITUTION: First water is filled up to a precribed water level in a settling tank 1 and a motor 13, a vibration generator 10 and a pump 17 are operated. When water mixed with sand and the like is next charged continuously through a mixed water supply port 26, the sand in the mixed water settles successively on a belt conveyor 2, and the remaining mixed water flows successively toward a discharge trough 8. The above-mentioned settled sand is successively conveyed by the belt conveyor 2, and is applied with vibrations by the vibrator 9 of the generator 10, whereby it is subjected to dehydration and desorption of impurities. Thence, it is conveyed to the outside of the tank 1. Further, a sucker is installed in the case of collecting sand from mixed water contg. much of pumice, wooden dust, etc.