A jet engine which includes: a fan with a plurality of stages of rotor blades; a compressor compressing air sent from the fan; a combustor generating combustion gas by using compressed air generated by the compressor; a turbine generating a driving force from the combustion gas; a nozzle discharging the combustion gas; a variable guide vane disposed upstream of the rotor blades of a second and later stage of the rotor blades of the fan and adjusts an inlet angle of air flow against the second and later stage of the rotor blades; a fluid resistance adjusting device adjusting a fluid resistance at the nozzle; and a controller which controlling the variable guide vane such that the inlet angle at the time of cruise flight is smaller than the inlet angle at the time of acceleration.