This gas turbine engine is provided with: a fan that is disposed on the front of a compressor and that rotates in conjunction with the rotational shaft; a casing that includes an inner shell having accommodated therein a compressor, a combustor, and a turbine and includes an outer shell forming, between the inner shell and the outer shell, a bypass through which part of air blown from the fan passes; a plurality of bearings disposed on the inner side of the inner shell; an oil mist generation device that is disposed outside the outer shell and that generates oil mist by mixing oil with compressed air extracted through an extraction port of the compressor; an air piping that guides the compressed air extracted from the compressor toward the oil mist generation device; and an oil mist piping that guides the oil mist generated by the oil mist generation device toward the plurality of bearings, wherein a heat exchanger part is disposed along the bypass so as to cool the air piping and/or the oil mist piping by the air passing through the bypass.