A mechanism to act as a buffer, the mechanism includes a base seat defining a chamber and a bottom hole communicating with the chamber; a connecting shaft received in the chamber and extending through the bottom hole, the connecting shaft including a blocking portion for preventing detachment from the base seat, the connecting shaft axially defining a receiving hole and a plurality of mounting holes communicating with the receiving hole; a guiding rod fixed to the base seat, one end of the guiding rod extending out of the base seat and an inserting portion at the other end, the inserting portion including an abutting surface tapered toward the distal end; a buffer sleeved on the connecting shaft; a plurality of rolling bodies in the mounting holes and providing resistance between the abutting surface and the buffer; and a resilient member between the guiding rod and the blocking portion.