The invention relates to a completely mechanical laparoscopic surgical instrument which can be disposed of after a single use or which can be sterilised and re-used more than once. The instrument essentially comprises: a gripping zone provided with two gripping elements (2, 3) hinged to one another by means of a pivot shaft (4), a working tool (30) provided with two jaws hinged to one another by means of a pivot shaft, and an actuation mechanism that can transmit movement from the gripping zone to the working tool (30). According to the invention, the tool can adopt multiple positions and/or orientations during its use with the assistance of substantially annular bodies that are coupled to connecting rods associated with the gripping elements.
