PURPOSE: To uniformly supply purging-gas into the oil passage side of each fuel nozzle by opening and closing the valves at a same time by using a ganged selector valve, when the purging-gas is supplied into the oil passage sides of a plurality of fuel nozzles.

CONSTITUTION: A plurality of fuel nozzles 1aW1h installed onto a combustor are connected to the respective fuel gas feeding pipes 6 and the fuel-oil feeding pipes 7, and a purging-gas feeding pipe 9 is connected to each fuel-oil feeding pipe 7. A ganged selector valve 11 having the valves 12 in the number corresponding to the number of fuel nozzles 1aW1h in a case body is installed and an outlet 13 corresponding to each valve 12 is connected to the outlet side of a check valve 8 through the purging-gas feeding pipe 9. Said outlet port 13 communicates to a common purging-gas inlet 14, which is connected to the purging- gas feeding pipe 9. Each valve 12 is connected to a servomotor 16 through a link 15, and the valves 12 are opened and closed at a same time.