The present invention provides a tailstock which securely clamps a tailstock barrel in working to prevent the barrel from chattering for keeping working accuracy of a workpiece and also enables a bearing member of the tailstock barrel to be easily replaced when the member has worn. The tailstock comprises a body having a through-hole, the tailstock barrel inserted into the through-hole and slidably and rotatablely supported, and a fluid pressure driver for driving the tailstock barrel to be pressed against the workpiece. The tailstock is equipped with a pair of bearing members which can be inserted between the through-hole and the tailstock barrel respectively from the side of the workpiece and the side opposite to the workpiece and axially separate from each other, and also equipped witha clamping device. The clamping device includes a hollow member provided to surround the tailstock barrel between the pair of bearing members and a high pressure fluid supplying device for supplying ahigh pressure fluid to an internal space of the hollow member. The hollow member is fixed to the body and also has a radially inward part pressing the tailstock barrel with an inflow of the high pressure fluid so as to clamp the tailstock barrel.