Abstract: A cylinder lock has a first tumbler, a second tumbler and a third tumbler all received in a hollow cylindrical housing. The first tumbler is selectively rotatable relative to the second tumbler and the second tumbler together with the first tumbler is selectively rotatable to the third tumbler. By pressing downward the actuating pin, a rearrangement between first tumbler pins and second tumbler pins by relative rotation of the first tumbler to the second tumbler adapts to a different key.