The present invention discloses a sliding mechanism including a first board, a second board, a first fixed piece, a frame, a first elastic element and a first sliding element. The second board includes a first slot. The first fixed piece passes through the first slot to be disposed on the first board. The first elastic element is disposed in the frame. When the second board slides a first distance relative to the first board, the first sliding element slides along a first direction to press the first elastic element, so as to make the first elastic element generate a first elastic force. When the second board slides a second distance relative to the first board, the first sliding element slides along a second direction and makes the first elastic element release the first elastic force. It makes the second board slide automatically relative to the first board.