To provide a control valve which has excellent control characteristic and cavitation characteristic and reliably removes foreign matters and eliminates any clogging by a simple operation without any complicated work even when clogging occurs by foreign matters including the refuse.

The control valve 1 comprises a valve casing 2, an outer valve element 3 penetrating a large number of ports 8, an inner valve element 4 accommodating the outer valve element 3, a main valve stem 5 and a sub valve stem 6. The quantity of the fluid is controlled by adjusting the open area of a port 8 by turning the inner valve element 4 around the second axis C2 in the fully closed condition in which the port 8 is fully closed, the fully opened condition in which the port 8 is fully opened, and the condition between the fully opened condition and the fully closed condition. When the port 8 is clogged, the outer valve element 3 is turned in the reverse direction by 180° from the fully closed position to reliably remove foreign matters by the cleaning effect by the flow of the fluid F.