The invention concerns a method for detecting a surgical tool on a first image comprising the following steps: storing shape parameters of the surgical tool; determining a second image (I3) containing distinct pixel regions from the first image by means of a first processing operation comprising the segmentation of the first image; determining first windows (F), each first window surrounding one of the regions; selecting at least one second window from among the first windows, from the shape parameters; determining a third image from the first image by applying, to the first image, a second processing operation implementing Frangi's algorithm; and determining lateral edges of the surgical tool on the part of the third image contained in said second window.