It is an object of the invention to provide a tap holder in which even when an error is brought about in synchronizing spindle feeding and rotation of a tapper body and a tap collet of a tap holder in correspondence with a machine tool spindle, the synchronization can be established by absorbing the error by a simple constitution. As means therefor, the tap holder is characterized in that a tapper body and a tap collet are inserted by a locking member at portions of the tapper body and the tap collet overlapping each other, and the tap collet is fixed to the tapper body by engaging the locking member with at least one of the tap collet and the tapper body in a state of being interposed with an elastic member on both sides thereof in an axial direction X.