Cylinder liner and reciprocating engine provided with same

The purpose of the present invention is to improve the recovery performance of a reciprocating engine, and to further reduce the weight thereof, thereby improving the environmental performance. A cylinder liner (30) according to the present disclosure is provided only in a portion of a region on the inner surface (21i) of a cylinder (21) of a reciprocating engine in which a piston ring (50) attached to a piston (40) that reciprocates in the cylinder (21) slides, and has a structure in which the overall length (L) of the liner in the axial direction of the cylinder (21) is smaller than the inner diameter (B) of the cylinder. Concave and convex parts are formed on one side lower end part (30d) which is the end part close to the bottom dead center side of the piston ring (50) in the axial direction. 往复运动发动机为了能够在回收性能方面有所改善，并且能够进一步实现轻量化，从而能够提高环境性能，本公开所涉及的气缸套（30）是以下结构：仅设置于往复运动发动机的气缸（21）的内表面（21i）中的、供安装于在该气缸（21）内往复运动的活塞（40）的活塞环（50）滑动的区域的一部分，沿着气缸（21）的轴向的套全长L比气缸的内径B小，在轴向上靠近活塞环（50）的下止点侧的端部即一侧的下端部（30d）形成有凹凸。