CHUCK DEVICE AND MACHINE TOOL

To enable a tool to machine a peripheral surface of an end part of a lengthy work-piece, while enhancing support rigidity of the work-piece.SOLUTION: A first chuck device 50 comprises a plurality of claw parts 52, provided in a first spindle 10 that can rotate, which grip and support a peripheral surface Wa of an end part of a lengthy work-piece W, and a center 53 that presses and supports an end face Wb of the work-piece W. Selectively either of the claw part 52 and the center 53 can advance and the other can retreat relatively to the end part side of the work-piece W along a direction of a rotation axis AX of the first spindle 10. The claw part 52 advances relatively with respect to the center 53 and then grips and supports the peripheral surface Wa of the end part of the work-piece W, and the center 53 advances relatively with respect to the claw part 52 and then presses and supports the end face Wb of the work-piece W.SELECTED DRAWING: Figure 1 【課題】長尺のワークの支持剛性を高めつつ、ワークの端部周面を工具により加工することを可能にする。【解決手段】第１チャック装置５０は、回転可能な第１主軸１０に設けられ、長尺のワークＷの端部周面Ｗａを把持して支持する複数の爪部５２と、ワークＷの端面Ｗｂを押圧して支持するセンタ５３と、を備え、爪部５２とセンタ５３とは、第１主軸１０の回転軸ＡＸ方向に沿って選択的にいずれか一方が相対的にワークＷの端部側に前進、他方が後退可能であり、爪部５２は、センタ５３に対して相対的に前進してワークＷの端部周面Ｗａを把持して支持し、センタ５３は、爪部５２に対して相対的に前進してワークＷの端面Ｗｂを押圧して支持する。【選択図】図１