An adjusted-free air cylinder includes a cylinder body, a piston, a first check valve, a second check valve, an upper flow channel and a lower flow channel. The cylinder body has an air chamber inside. The piston is extended out of the cylinder body on the end and slides as reciprocating motion in the air chamber. The air chamber is separated into an upper chamber and a lower chamber. The first check valve is disposed in the piston, and has one end connected to the upper chamber and the other end connected to the lower chamber. The upper flow channel connected to the upper chamber and the outside of the cylinder body. The second check valve is disposed in the upper flow channel, and has one end connected to the upper chamber and the other end connected to the upper chamber. The lower flow channel is connected to the lower chamber and the outside of the cylinder body. The adjusted-free air cylinder has simple structure, good performance of buffer and lower prime cost. Further, it doesn’t need adjustment, so that it has high competitiveness in the market.一種免調整之緩衝氣壓缸包括一氣壓缸本體、一活塞件、一第一逆止閥、一第二逆止閥、一上通氣道及一下通氣道。氣壓缸本體內部形成一氣壓室；活塞件滑設於氣壓室內，一端延伸至氣壓缸本體外，活塞件在氣壓室內往復地移動且將氣壓室分隔為一上氣室及一下氣室；第一逆止閥設置於該活塞件內，其一端連通上氣室，另一端連通下氣室；上通氣道連通上氣室及外界；第二逆止閥設置於上通氣道內，其一端連通外界，另一端連通上氣室；下通氣道連通下氣室及外界。免調整之緩衝氣壓缸不需調整進氣流率，可隨著使用者步行的速度而自動調整進氣流率以產生緩衝阻力，且結構簡單、緩衝性能高、成本低廉，極具市場競爭力。
