Provided is a tap holder configured so that compression-side elastic characteristics and tension-side elastic characteristics are different from each other with utilization of an elastic member for absorbing synchronization error in rotation and feeding of a spindle of a machine tool. The tap holder includes a chuck 20 for holding a tap P, and a holder body 10 for holding the chuck 20 so that the chuck 20 is movable along a rotational axis X and rotatable in synchronism with the chuck 20. The tap holder further includes elastically deforming members 31, 32, 33 provided in a tension direction and a compression direction, respectively and deformable between the chuck 20 and the holder body 10 when a tension force or a compression force is applied to the tap P along the direction of the rotational axis X, and a deformation reducing mechanism 29 for the elastically deforming members 31, 32, 33 such that a deformation amount along the rotational axis X generated in at least one elastically deforming member 31, 32 of the elastically deforming members 31, 32, 33 disposed respectively in the tension direction and the compression direction is smaller than an amount of displacement of the chuck 20 along the rotational axis X.