Abstract: A small-sized and inexpensive air cylinder with a cushion mechanism having a simple structure is provided. Therefore, discharge outlets for discharging cushioning air are disposed in positions closer to ends of the stroke than the openings of the ports in the cylinder tube, respectively, and check valves and throttling mechanisms are arranged in parallel between discharge outlets and ports, respectively. On the outer peripheral surface of the piston, one of the piston packing rings is disposed in one position which does not pass through the opening of the port while another of the piston packing rings is disposed in another position which passes through the opening but does not pass through discharge outlet, when the piston reaches the terminal ends of the stroke.