A surgical instrument with two legs movable relative to each other is provided. A tip inserted in a receiving space at the distal end of each leg is exchangeably held at the free end of the leg. A two part fixing device is provided for releasable fixation of the tip to the leg, the fixing device having on one of the parts two locking arms which are arranged next to each other and are elastically bendable apart, and on the other of the parts a locking projection extending into the leg transversely to the direction of insertion. The locking projection, when inserting the tip into the receiving space, engages between the locking arms, bending them apart, and at the end of the inserting movement, enters a recess on the inner side of the locking arms. The receiving space widens in the proximal direction from its insertion end.