1. An apparatus for supplying document, comprising: a storage unit configured to store therein a set of documents and an affiliation within an organization paired up with one of the documents; a unit configured to receive a request for accessing said one of the documents; a unit configured to check an affiliation of a person who made the request; a unit configured to evaluate a relationship between the checked affiliation and the stored affiliation paired up with said one of the documents in a tree structure representing a hierarchical structure of the organization with nodes of the tree structure representing affiliations within the organization; a unit configured to ascertain a level of disclosure with respect to said one of the documents in response to the evaluated relationship; and a unit configured to control disclosing of said one of the documents according to the ascertained level of disclosure.