A tool holder is equipped with a tip run-out correction mechanism for correcting run-out of the tip of the tool. The tip run-out correction mechanism includes an annular stepped portion formed on a cylindrical support portion of a holder body; a ring member rotatably fitted onto the annular stepped portion; an eccentric cam disposed within the ring member, the eccentric cam extending radially through the ring member and being rotatable about a radially extending axis; and a pin disposed within the ring member to be movable along a direction parallel to the center axis of a flange portion of the holder body. One end of the pin is in contact with the eccentric cam, and the other end of the pin is in contact with a rear end face of a clamp sleeve which clamps a tool inserted into a chuck sleeve of the holder body. The eccentric cam is rotated so as to adjust press force that the pin applies to the rear end face of the clamp sleeve, to thereby elastically deform a base end portion of the chuck sleeve in a radial direction in such a manner that tip run-out of the tool approaches zero.