To provide a tool holder constituted of a body having a connection mechanism and adjustable in an axial direction, wherein a movable part for mounting a tool is slidably mounted in a recessed part of the body.

The movable part 3 for mounting the tool 4 cooperates with an adjustment ring 5 in the lateral direction. The adjustment ring 5 in the lateral direction is fixed to a tip end part of the body 1 including the recessed part 2 for mounting the movable part 3 for mounting the tool 4 in the lateral direction with respect to the tip end part by using a ball bearing device 8 and provided in a form of a sleeve having an internal screw 5' to be provided. The ball bearing device 8 imparts an axial play for assuring to press a proximal surface 51 of the adjustment ring 5 with respect to a distal external support flange 1' corresponding to the body 1 when the movable part 3 is clamped, and the movable part 3 is locked to an operating position after being adjusted using a clamping tool by at least one drag force cooperating with a portion 7 corresponding to the movable part 3.