A gas turbine engine, in which a compressed gas from a compressor of an axial-flow type is burned in a combustor and an obtained combustion gas drives a turbine, includes: a diffuser of an annular shape connected to an outlet of the compressor, the diffuser including a diffuser inner tube and a diffuser outer tube that are tubular members disposed concentrically with each other; and a plurality of partition members that are disposed in a diffuser flow path, which is an annular space formed between the diffuser inner tube and the diffuser outer tube, and divide the diffuser flow path in a circumferential direction.