To provide a kind of a mouthpiece to certainly fix materials tong holds of which are different from each other.

A step mouthpiece 5 has a fixing part 6 to fix on a vice and a movable part 7 height of which is low in comparison with the fixing part 6. It is possible to certainly hold the plat type material W1 by making a closed area of a step part 5a against a side surface of the plate type material W1 and a lower surface of it optimum by using it by reducing a step difference A on the step part 5a of the step mouthpiece 5 in the case of holding the plate type material W1. It is possible to more strongly and more certainly hold the block type material W2 by making the closed area of the step part 5a against a side surface and a lower surface of the block type material W2 optimum by using it by increasing the step difference A on the step part 5a of the step mouthpiece 5 by lowering a position of the movable part 7 against the fixing part 6 in the case of holding the sufficiently thick block type material W2.