A sliding mechanism includes a first plate, a second plate, a fixing structure and a sliding member. The second plate includes a sliding slot and a guiding part. The fixing structure has a perforation. The sliding member includes a sliding piece and an elastic element. The fixing structure is penetrated through the sliding slot of said second plate. A first end of the sliding piece is sustained against the guiding part. A second end of the sliding piece is penetrated through the perforation. When the second plate is slid with respect to the first plate for a first predetermined distance, the elastic element generates elastic potential energy. Whereas, when the second plate is slid with respect to the first plate for a second predetermined distance, the elastic element releases the elastic potential energy to have the second plate automatically slide with respect to the first plate.