A sliding mechanism includes a main board, a sliding board, two racks, a gear, a connecting member and a winding coil. The main board defines a guiding slot. The two racks are positioned at two opposite sides of the main board. The gear matches each of the first and second racks. The sliding board is slidable along the guiding slot by the connecting member. The winding coil, the winding coil is tightened when the sliding board is pushed toward or away from the main board, and rebounds to its original shape to cause the sliding board to automatically further slide relative to the main board when the gear is detached from one rack and matches another rack.