The present disclosure provides a gas flow regulating device and a mass flow controller. The gas flow regulating device includes: a valve port component, in which a first inlet channel is provided; a push rod component, in which a first through hole is provided, a push rod being provided in the first through hole, a first end surface of the push rod facing a gas outlet end of the first inlet channel, and the push rod being elastically connected with the push rod component through an elastic diaphragm; and a driving assembly configured to drive the push rod to move along a direction of approaching or leaving the first inlet channel to cause the first end surface of the push rod to be in contact with and seal or separate from the gas outlet end of the first inlet channel. In the gas flow regulating device, the structure can be simplified, the number of parts in contact with gas can be reduced, and the fault caused by the failure of a spring piece can be avoided.