PURPOSE: To remove contaminants from the washing, etc., by fixing the washing inside of a washing trough, and allowing detergent water in the trough to flow.

CONSTITUTION: An inner vessel to hold the washing, etc., is made of a rust-free material in the form of a cage having good penetrativeness such as wire meshing, basket, etc., and is put with the washing in a washing trough can be enclosed. As if a piston this inner vessel is secured in the central part inside of the trough which assumes as if a cylinder. Thus inside of the trough forms two chambers owing to the inner vessel. A water path is provided to die these two chambers, and a pump of specified configuration such as a volute pump is installed on this water path. Through the action of this pump the detergent or water in the trough flows from one chamber to the other unidirectionally, and contaminants are removed when it passes through the washing accommodated in the inner vessel.