In an airtight suction device and a rotary switch thereof, the airtight suction device includes a main body having a communication space and a plurality of connectors. These connectors include a suction connector, a respiratory connector, a cleaning connector, and a control valve connector. The rotary switch is provided on the control valve connector and includes a rotary cover and a hollow post. The hollow post has a peripheral wall and a blocking piece. The peripheral wall is provided with a pair of suction holes. The blocking piece is provided with a ventilation hole for allowing external air to flow into the suction holes.
