A noise reduction system with a chamber includes a chamber (17) which is provided at a portion of a supply path connecting a flow path in an upstream side of a combustor in a jet engine to a plurality of microjet nozzles which is provided at an exhaust side peripheral edge of a main nozzle of the jet engine, wherein the supply path is configured to supply part of compressed air from the flow path into the chamber (17), and the chamber (17) is configured to inject the compressed air through the plurality of the microjet nozzles (63) to a jet flow.