To provide a gas flow control valve for accurately controlling a flow rate of gas alternatively selected from a plurality kinds of gasses.

A gas proportional control valve 32 can adjust a flow rate of fuel gas flowing in a fuel gas passage 43. Since a driving mechanism 42 for driving a valve element 41 has a stepping motor 50, and two sets of gear mechanisms 53 and 54 having the different gear ratio interposed in a driving force transmission system for transmitting rotational driving force of this stepping motor 50 to the valve element 41, that is, the two sets of gear mechanisms 53 and 54 respectively corresponding to the plurality kinds of gasses, when selecting a certain kind of fuel gas, the flow rate of the fuel gas can be accurately adjusted by switching to the gear mechanism having the gear ratio optimal for controlling the flow rate of the selected fuel gas.