Abstract: A cock according to the present invention comprises a cylindrical main body, a plug inserted into the main body liquid-tightly so as to be turned normally and reversely, a mounting flange mounted to the main body, a first cock part permitting a first inflow port and a first outflow port on the main body side to be opened and closed through a first connection port on the plug side, and a second cock part permitting a second inflow port and a final outflow port on the main body side to be opened and closed through a second connection port on the plug side, wherein the final outflow port is formed in the main body along a perpendicular direction, and the first cock part is controlled to start opening slightly later than the second cock part and also to start closing slightly earlier than the second cock part.