To provide a gas turbine engine which is simple in structure but can effectively remove foreign matters from the combustion air.The intake passage 21 includes an inlet portion 29, a curved portion 30 and a reduced diameter portion 31. The bypass duct 24 is curved away from the central axial line CL in a region corresponding to the curved portion 30 and reduced diameter portion 31 of the intake passage 29. Between the intake passage 29 and bypass duct 24 is defined an annular space 32. In the reduced diameter portion 31, the outer liner 20 is formed with a large number of foreign matter introduction openings 33 in a circumferential arrangement for communication between the intake passage 21 and annular space 32. The inner casing 4 is formed with a plurality of foreign matter ejection holes 34 in a circumferential arrangement in a part thereof that curves outward for communication between the annular space 32 and bypass duct 24.