A fuel injection device for injecting an air-fuel mixture to a combustion chamber in a combustor of a gas turbine engine, the fuel injection device comprising a fuel injector arranged on an axis of the fuel injection device having a cylindrical outer wall, a tubular wall that covers an outer circumference of the fuel injector, the fuel injector including: a fuel injection portion having a plurality of fuel injection nozzles and configured to inject fuel in a radial direction of the fuel injection device; a fuel flow path portion forming a passage configured to supply fuel therethrough to the fuel injection portion, a heat shield cover including a cover portion that covers an end portion facing toward the combustion chamber side of the fuel injection portion and a cover support portion that supports the heat shield cover with respect to the fuel flow path portion, such that an air layer is formed between the heat shield cover and the end portion, the heat shield cover having nozzle window holes opening toward outer side and formed at respective portions of the heat shield cover that corresponds to respective fuel injection ports of the fuel injection nozzles, and the tubular wall forms an air passage on an inner side of the tubular wall, characterized in that the air layer communicates with an outer space via only gaps between the fuel injection nozzles and the nozzle window holes of the heat shield cover, each of the gaps being so small that air does not flow in or out between the outer space and the air layer in a state where air flows in the air passage. a fuel injector arranged on an axis of the fuel injection device having a cylindrical outer wall, a tubular wall that covers an outer circumference of the fuel injector, the fuel injector including: a fuel injection portion having a plurality of fuel injection nozzles and configured to inject fuel in a radial direction of the fuel injection device; a fuel flow path portion forming a passage configured to supply fuel therethrough to the fuel injection portion, a heat shield cover including a cover portion that covers an end portion facing toward the combustion chamber side of the fuel injection portion and a cover support portion that supports the heat shield cover with respect to the fuel flow path portion, such that an air layer is formed between the heat shield cover and the end portion, the heat shield cover having nozzle window holes opening toward outer side and formed at respective portions of the heat shield cover that corresponds to respective fuel injection ports of the fuel injection nozzles, and the tubular wall forms an air passage on an inner side of the tubular wall, characterized in that the air layer communicates with an outer space via only gaps between the fuel injection nozzles and the nozzle window holes of the heat shield cover, each of the gaps being so small that air does not flow in or out between the outer space and the air layer in a state where air flows in the air passage. a fuel injection portion having a plurality of fuel injection nozzles and configured to inject fuel in a radial direction of the fuel injection device; a fuel flow path portion forming a passage configured to supply fuel therethrough to the fuel injection portion, a heat shield cover including a cover portion that covers an end portion facing toward the combustion chamber side of the fuel injection portion and a cover support portion that supports the heat shield cover with respect to the fuel flow path portion, such that an air layer is formed between the heat shield cover and the end portion, the heat shield cover having nozzle window holes opening toward outer side and formed at respective portions of the heat shield cover that corresponds to respective fuel injection ports of the fuel injection nozzles, and the tubular wall forms an air passage on an inner side of the tubular wall, characterized in that the air layer communicates with an outer space via only gaps between the fuel injection nozzles and the nozzle window holes of the heat shield cover, each of the gaps being so small that air does not flow in or out between the outer space and the air layer in a state where air flows in the air passage.