Abstract: A tissue thickness measuring instrument for surgical purposes comprising a pair of opposed tissue engaging jaws. Manually graspable actuating means operatively connected to the jaws for shifting the jaws away from each other. A resilient means urges the jaws toward each other with a substantially constant predetermined force over a predetermined working range of separation distance between the jaws. At least one scale with cooperating indicator is provided in association with the jaw actuating means giving a direct reading of the thickness of the tissue being measured. The instrument may be provided with another scale by which the diameter of tubular body elements in the flaccid state can be determined.