Abstract: A needle-roller type chuck for machine tools which includes a chuck body having a chuck barrel integral with the leading end portion of the chuck body. The chuck barrel has a leading end portion and an outer peripheral surface tapered to form a conical surface, and includes a plurality of holes extending from the leading end of the chuck barrel toward the chuck body. A rotatable clamping ring is positioned over the chuck barrel and has an inner conical surface extending in the axial direction of the chuck and parallel with the outer periperal surface of the chuck barrel. A needle-roller assembly having a plurality of needle rollers is positioned between the chuck barrel and the clamping ring in rotatable contact with the conical surface of the chuck barrel and the clamping ring.