To provide a technique for executing authentication processing on a user, at a high speed.

A communication controlling device includes a first database 50 stored with authentication information for authenticating a user; a retrieval circuit 30 which acquires communication data for requesting authentication of the user and retrieves authentication information on the user, included in the communication data from the first database 50; and a processing execution circuit 40 which transmits communication data for answering the result of the authentication of the user to the request source according to a retrieval result obtained by the retrieval circuit 30. The communication controlling device has a plurality of databases for a plurality of different kinds of communication control as the first database 50 and a second database 60, and further, includes a switching unit 180, which enables the communication controller to perform the plurality of different kinds of communication control by changing the database.