Non-invasive device for locating a structure (N2), such as a nerve, in a region of a body having an external surface (Se), the device comprising: a focused ultrasonic transducer (1), advantageously of the HIFU type, designed to produce an ultrasound beam (Fu) through the external surface (Se) in the region, the beam (Fu) having a focal point that can be positioned on the structure (N2) monitoring means (3) for detecting a response of the structure when this is subjected to a stimulation and stimulation means (1 4) for stimulating the structure (N2), which delivers a response detected by the monitoring means (3), the stimulation means comprising the ultrasonic transducer (1) capable of delivering an ultrasound beam (Fu) to said structure (N2), so as to disturb it, characterized in that the device includes: an imager (2, 21, 22) mechanically coupled to the ultrasonic transducer (1) so that the imager follows the focal point of the transducer so as to display, on an image, the position of the focal point of the ultrasound beam (Fu) in said region of the body and marking means, for marking the position of the structure (N2) in the image produced by the imager.Dispositif de repérage non invasif dune structure (N2), telle quun nerf, dans une zone dun corps ayant une surface externe (Se), le dispositif comprenant : - un transducteur ultrasonore focalisé (1 ), avantageusement du type HIFU, adapté à produire un faisceau dultrasons (Fu) à travers la surface externe (Se) dans la zone, le faisceau (Fu) ayant un point focal capable dêtre positionné sur la structure (N2), - des moyens de monitoring (3) pour détecter une réponse de la structure lorsque soumise à une stimulation, et - des moyens de stimulation (1 4) pour stimuler la structure (N2) qui délivre une réponse détectée par les moyens de monitoring (3), les moyens de stimulation comprennent le transducteur ultrasonore (1 ) capable de délivrer un faisceau dultrasons (Fu) à ladite structure (N2), pour la perturber, caractér
