A stud locking tool is equipped with a first clip and a second clip for sandwiching a mounting member. The mounting member is mounted in a member to be mounted by locking the stud. The first clip has a hollow inner cylindrical portion inserted into a mounting hole of the mounting member. A first flange is located at one end of the inner cylinder portion, and a locking claw is formed inside the inner cylindrical portion and engages with a thread of the stud. The second clip has a hollow outer cylinder portion sized to surround the inner cylinder portion of the first clip. A second flange is located at one end of the outer cylinder portion. An engagement claw extends from the outer cylinder portion and engages the first clip. An inclined surface adjacent to the outer cylinder portion includes a stud guiding surface.