A gas turbine engine includes: a fan that is in front of a compressor and rotates in association with a rotating shaft; a casing including an inner shell and an outer shell and a bypass passage; bearings inside the inner shell; an oil mist generator that is outside the outer shell and generates oil mist by mixing oil with compressed air extracted through an extraction port of the compressor; an air pipe through which the compressed air extracted from the compressor is guided to the oil mist generator; and an oil mist pipe through which the oil mist generated by the oil mist generator is guided to the bearings. At least one of the air pipe and the oil mist pipe includes a heat exchanger that is in the bypass passage and is cooled by the air flowing through the bypass passage.