Abstract: An angle adjustment mechanism includes an angle adjustment block including first opposing side faces inclined relative to the direction along the rotation axis of the turret; first and second adjustment blocks having inclined faces that are brought into surface contact with respective first opposing side faces, and movable in a direction along the rotation axis; a depression formed in a tool holder, and accommodates the angle adjustment block with the first and second adjustment blocks; first and second adjusters that move the first and second adjustment blocks in a direction along the rotation axis of the turret; and a first positioning member conducting positioning between the turret and the tool holder, and a second positioning member conducting positioning between the turret and the angle adjustment block. This configuration provides a mechanism for attaching a tool holder to a turret which can easily conduct highly precise angle adjustment.