A surgical system for bonding body tissue includes a surgical instrument having tool elements movable relative to each other, each of which includes an HF electrode defining a minimum distance from each other, being opposed to each other and facing each other in an approximating position of the tool elements so as to bond body tissue held between the tool elements, and including a cutting element for transecting and/or resecting body tissue, the cutting element being adapted to be brought from a tissue bonding position, in which body tissue can be bonded to the tool elements and in which the cutting element cannot contact body tissue, into a cutting position such that faulty operation of the system is minimized. The instrument includes a means for retaining the cutting element in the tissue bonding position. An improved control method for a surgical system for bonding body tissue is also described.