To utilize an existing structure without the addition of a new machining as it is and not to require a piping and evade the bumping and piling of chips.

This machine tool is provided with a turret head 8 for holding plural tool holders, an index mechanism 10 for indexing the turret head 8 so that a required tool holder is positioned to a machining position and a rotary tool drive mechanism 22 for rotatingly driving the rotary tool of the tool holder indexed to the machining position. A work attaching/detaching mechanism 15 provided on the turret head 8 is provided with a drive rod 17 rotatingly driven by the rotary tool drive mechanism 22, a ball nut 18 screwed on the drive rod 17 and a pair of claw parts 20, 20 moved in the axial orthogonal direction of the drive rod 17 by the movement of the ball nut 18 in the axial direction of the drive rod 17 and a work is attached/detached by utilizing the rotation of the rotary tool drive mechanism 22.