1. A policy management apparatus comprising: a role information storing unit that stores role information including information indicative of subject sets to which policies are to be applied, and information capable of specifying inclusion relationships between subject sets contained in said role information; a policy description storing unit that stores policy descriptions including information indicative of policies and information for identifying subject sets to which said policies are to be applied; a policy stratifying unit that, for two or more policies stored in said policy description storing unit, generates a policy hierarchy in which two or more policies are stratified based on inclusion relationships between subject sets to which each policy is applied by assuming that each policy is a node; and a policy ordering unit that totally orders policy sets made of said two or more policies to be totally ordered based on information indicating a policy hierarchy generated by said policy stratifying unit while maintaining a higher/lower relationship in a hierarchy.