The present invention provides a nitrogen-containing saturated heterocyclic compound of the formula [I] which is useful as a renin inhibitor. wherein R 1 is a cycloalkyl group or an alkyl, R 22 is an optionally substituted aryl and the like, R is a lower alkyl group, R 3 , R 4 , R 5 and R 6 are the same or different, and are a hydrogen atom, an optionally substituted carbamoyl, an optionally substituted alkyl, or alkoxycarbonyl, or a pharmaceutically acceptable salt thereof.