Anaesthesia machine and flow meter thereof

The invention provides an anaesthesia machine and a flow meter thereof. The flow meter comprises a plurality of air channels, each of the air channels comprises an air inlet, an air outlet and a control valve, and the air inlet and the air outlet are connected through the control valve. The control valve comprises a casing with a cavity, the casing comprises a first end and a second end, the first end is provided with a through hole, and the second end is provided with an inlet, an outlet and a valve port. The control valve further comprises a valve rod, the first end of the valve rod is arranged in the cavity of the casing, and the second end of the valve rod penetrates through the through hole at the first end of the valve rod to be exposed out of the casing. The valve rod is in threaded connection with the cavity, a first limit position and a second limit position are arranged respectively longitudinally on the valve rod, a limited portion is arranged between the first limit portion and the second limit position on the casing, and the second end of the valve rod is adjustably arranged between a blocked position and an open position of the control valve of the valve port corresponding to the valve rod. By the aid of threads between the valve rod and the cavity of the casing, flow can be controlled accurately.