PROBLEM TO BE SOLVED: To provide a wire tail automatic adjustment system for a wire bonder for preventing a wire tail from inappropriately extending from a capillary when wedge wire bond is formed, and of which the production capacity of a wire bonding device is increased.SOLUTION: A wire holder 16 is installed for fixing a wire while a wire clamp part 18 opens and does not tighten the wire 12. The wire clamp part and a capillary 20 are lifted up toward the wire holder in the direction to be separated from wedge wire bond to the wire in order to draw the wire with predetermined length. At predetermined height, the wire clamp part closes in order to tighten the wire, the capillary and the wire clamp part are moved so as to be further separated from the wedge wire bond. Thus, the wire is cut from the wedge wire bond, and a wire tail with desired length extending from the capillary is formed.