Patent ID: 7037052

Claim:
A spindle unit of a machine tool comprising: a spindle head in which a tool spindle is rotatably provided; a column supporting the spindle head movably in an up and down direction; a draw bar inserted into a through hole of the tool spindle, the draw bar is movable in an axial direction thereof, thereby clamping and unclamping a tool to be attached; an urging device urging the draw bar toward a clamping direction; an unclamping apparatus for moving the draw bar toward an unclamping direction; and a holding mechanism for holding the unclamping apparatus with the column, wherein the unclamping apparatus is able to be detached from the spindle head while being held in the column, and the spindle head is able to move in the up and down direction without having the unclamping apparatus, and wherein that the holding mechanism includes a hanging jig attached by utilizing a hole formed at an upper wall portion of the column for hanging to hold the unclamping apparatus.