An apparatus for stuffer box crimping a synthetic filament thread includes a thread inlet duct for aspiring and guiding synthetic filament threads to a stuffer box. The apparatus includes a flow duct, the thread inlet duct preceding the flow duct, the flow duct and the thread inlet duct having a common longitudinal axis. The apparatus is provided with a nozzle having an outlet opening merging into the flow duct, for supplying a fluid under pressure. The two or more sets of nozzles may be arranged consecutively along the longitudinal axis of the thread inlet duct and the flow duct in a direction of thread transport.