PURPOSE: To provide a method and device for analyzing operation sound of a jet engine, which can specify the cause for generating the specified sound on the basis of the operation sound of the jet engine.

CONSTITUTION: The device is provided with a reference microphone 12 fitted to a part near an opening part 1a of a jet engine 1, a cylindrical duct 14, of which one end is adhered to the opening part 1a of the jet engine 1 and of which the other end is opened and which is arranged concentrically with the jet engine 1, and a measuring microphone 16 fitted to the duct 14. The duct 14 is rotated around an axis Z thereof, and while pressure 7 of the operation sound of the jet engine 1 is measured by the reference microphone 12 and the measuring microphone 16, and a phase difference of the operation sound is computed on the basis of the pressure measured.by the reference microphone 12 and the measuring microphone 16, and a mode of the operation sound is computed on the basis of this phase difference.