To provide a fuel gas heating control system for a gas turbine, in which the gas flow rate is prevented from fluctuating caused by temperature change by furnishing a heater in a fuel gas system, and controlling the gas flow rate passing through the heater.

From a gas fuel system 11, a gaseous fuel is supplied to a combustor 10 through a fuel flow regulating valve 12. The gas temp. sensed by a temp. sensor 4 is fed to a control device 1, and in a setting device 2, the optimum temp. is set previously. The control device 1 compares the sensed temp. with the set value, and if the gas temp. is low, the gas quantity passing through a heater 3 and a heater bypass control valve 13 is controlled so as to bypass the heater, and thereby change in the gas temp. is suppressed. Accordingly the gas flow rate follows accurately after the fuel flow rate control signals 20.