PURPOSE: To provide a rocket engine capable of suppressing vibratory combustion to conduct the stable combustion in a wide operating range.

CONSTITUTION: A rocket engine comprises a combustion chamber 3 of a rocket engine, a vibration sensor 5 disposed in an injector 1 or a required position in piping or the like and at least one of valves 11, 12 for suppressing vibration by controlling combustion pressure or air fuel ratio on the basis of vibratory combustion sensed by the vibration sensors 5 and an acoustic cavity 2a for suppressing the vibration by changing an opening area, volume, etc., on the basis of the vibration.