A fuel injection device for a gas turbine combustor includes: a pilot fuel injector; a main fuel injector; a plurality of main fuel injection holes arranged in the main fuel injector to inject the fuel rearward; a main fuel injection nozzle to guide the fuel to a main air passage, protruding rearward from a circumference of the main fuel injection hole into the opening formed in a passage wall that forms the main air passage; a heat-shielding casing covering the main fuel injector; and a ring member interposed in an axial gap between the passage wall and the heat-shielding casing. The ring member covers a through-hole gap between the main fuel injection nozzle and a through-hole in the heat-shielding casing, and has a purge passage communicated with the opening to introduce air into the main air passage.