A device for the anchoring of a suture in tissue includes a guide sleeve, a sonotrode, an anchor and the suture. The guide sleeve has a distal part with a smaller cross section and a proximal part with a larger cross section. The sonotrode extends through the lumen of the guide sleeve and has a distal end and a proximal end, the proximal end being designed for coupling the sonotrode to a vibration source (e.g. an ultrasonic device). The anchor is arranged at the distal end of the device and includes an anchor foot and an anchoring sleeve sitting on a shoulder of the anchor foot. The anchoring sleeve consists of a material which is liquefiable through mechanical vibrations. A middle portion of the suture runs through the anchor foot and two end portions of the suture are attached to the guide sleeve.