The invention relates to an automatic binding machine which comprises a rack, a second motor, a drilling device, a lifting base, a paper pressing device, an upper hot-riveting head, a cutter pad and a lower hot-riveting head. A vertical guide column and a horizontal work table board are arranged in the rack. The lifting base is located on a vertical guide rail in a lifting manner. The paper pressing device is located between the lifting base and the work table board through springs in a lifting manner. The upper hot-riveting head is arranged in the paper pressing device and can horizontally move. The cutter pad is arranged on the work table board and can horizontally move. The lower hot-riveting head is located on the vertical guide column on the lower side of the horizontal work table board and can ascend, descend and rotate. A first rotating connecting rod arranged among the upper hot-riveting head, the cutter pad and the lower hot-riveting head is in rotating linkage. The second motor is connected with the first rotating connecting rod to switch over horizontal dislocation movement between the upper hot-riveting head and the cutter pad and drive the lower hot-riveting head to do rotating dislocation movement. The automatic binding machine can achieve linkage switchover of the upper hot-riveting head, the cutter pad and the lower hot-riveting head through the single motor, and has the advantages that the structure is simple, transmission is reasonable, machining is achieved, and the size and cost are reduced.