In an access right management system and method which manage access to data and prevent the data from leaking, a plurality of associated users who possess access rights to data are registered in a user account database, users who agree to the access to the data at present among the access right possessing users are registered in an active user database, and an access agreement portion agrees, only when a present number of access right possessing users having agreed and registered in the active user database is plural, to the access to the data with access right possessing users who have requested the access to the data.