To provide a clamp holder for an aligning device capable of clamping an optical component securely by constant pressing force.

The optical component W to be clamped is put on a workpiece loading base 3, and its one end abuts on a clamp jaw 35 on fixed side provided on the workpiece loading base 3. A clamp jaw 25 on moving side provided for a clamp base 5 on moving side so as to move freely is pressed against the other end of the optical component W by energizing force of a spring incorporating screw 29 to clamp the optical component W. At this time, moving origin of the clamp jaw 25 on moving side is moved and adjusted in accordance with size of the optical component W by the clamp base 5 on the moving side. Moreover, the clamp base 5 on the moving side is moved in the direction of the clamp jaw 35 on the fixed side by predetermined distance by a clamp force setting screw 15 using the moving origin of the clamp jaw 25 on the moving side as reference to generate energizing force of the spring incorporating screw 29.