The utility model discloses a fastener adjusting device, and belongs to the technical field of machinery. The device comprises a rotating piece, a connecting piece and a curved bar, the first end of the rotating piece is used for being fixedly connected with the fastener, and the second end of the rotating piece is connected with one end of the connecting piece; wherein one end of the connecting piece is connected with the bent lever, the other end of the connecting piece is connected with the bent lever, the bent lever comprises at least two rod parts and at least one connecting part, every two rod parts are connected through one connecting part, and the extending directions of the two rod parts connected through the same connecting part are crossed; the curved bar is configured in the mode that when the curved bar moves relatively, the rotating piece is driven by the connecting piece to rotate, so that the fastening piece fixedly connected with the rotating piece rotates. The fastener adjusting device solves the problem that the efficiency is low when the fastener is adjusted, and is used for fastening the fastener.