The invention relates to the technological use of ultrasound energy and can be used in various branches of industry, particularly in technological processes, connected with filtering, decontamination of liquids, clarification of waste water, activation of liquids and fuel, etc. The device for ultrasound cavitation treatment of liquid comprises acoustically untied with inlet and outlet flange-nozzles tube for liquid passage, ultrasound vibration drives, additional tube with the formation of overlapped for liquid passage tube space, pin hole, connected with the inner surface of the additional tube, besides the external surface of additional tube is made conical with the incline against the liquid current.