The present invention provides a nitrogen-containing saturated heterocyclic compound of the formula [I]: wherein R 1 is a cycloalkyl group and the like, R 22 is an optionally substituted aryl and the like, R is a lower alkyl and the like, T is a carbonyl group, Z is -O- and the like, and R 3 to R 6 are the same or different and a hydrogen atom and the like; or a pharmaceutically acceptable salt, that is useful as a renin inhibitor.