Access control with easy change/extension is implemented. Access to data is controlled by a first storage unit that stores a plurality of attribute values respectively selected from a plurality of integers which are relatively prime and identifying a plurality of attributes of users, in association with respective users a second storage unit that stores a product of at least two attribute values which are common to users belonging to a set of users, in association with respective data to be accessed, to show the set of users which are targets of controlling access to the data. A plurality of attribute values corresponding to a user who requests access are read from the first storage unit, and a product of at least two of the plurality of read attribute values is calculated. The user is accepted as a target of controlling access to the data, on condition that the calculated product of attribute values matches a product of attribute values stored in the second storage unit in association with the data to be accessed.