A surgical apparatus, including an instrument, a shaft part with a jaw opening at its distal end and a thread carrier guided by the shaft part displaceable from a retracted position, in which it exposes the jaw opening, and an advanced position, in which it crosses the jaw opening. A thread supported by the thread carrier can be guided through or around human or animal tissue to form a suture or ligature. The thread has a bulge at its end made of the material of the thread so that when the bulge is pushed through a passage opening of the jaw part it elastically deforms and is retained when the thread carrier is retracted.