Abstract: A cutting tool for tissue surgical resection instruments, such as electric or ultrasonic bistoury, includes a connector element (5) supported in its upstream portion by the bistoury, a thin cutting element (7) integral with the connector element (5), and forming a plane, and a guide element (15) spaced apart from the cutting element (7) by a distance (b) equal to the thickness of the tissue elements to be removed and designed, during the cutting procedure, to be urged in contact with the surface (1) thereof. The guide element (15) is located in the cutting element plane, and its surface (1) adapted to be urged in contact with the tissues is larger than the corresponding surface of the cutting element (7).