A device treats a thread with compressed air. To this end, the device has an intermingling device which is encapsulated in a housing with respect to the environment. For thread guidance, the housing has a thread inlet and an opposite thread outlet. In order to prevent direct transmission of noise through the thread inlet and the thread outlet, the thread inlet and/or the thread outlet is formed in each case by two separate opening slots in quick succession and a thread guiding member between the opening slots.