A clamping structure is assembled in a handpiece (3). An embodiment of the clamping structure includes a connecting member for clamping a dental tool (5) and a controlling member (2). Two or more clamping portions (13) are disposed on the connecting member and a distance between the clamping portions (13) is changeable due to a control over the clamping portions (13). The controlling member corresponds to the connecting member and is abutted against the clamping portions (13). The controlling member (2) can be moved relative to the clamping portions (13) to form the control over the clamping portions (13) so as to allow the clamping portions (13) to clamp or to release the dental tool (5). A tungsten carbide coating layer is disposed on a contact surface of the controlling member (2), contact surfaces of the clamping portions (13), or both.
