To hold only necessary data in relayed data as history information.

A request analyzing means 23 receives a request for obtaining data from a data using means 11, and analyzes whether or not a request for obtaining data is a request for relaying data or a request for obtaining history information. When the request for obtaining data is a request for relaying data, the request analyzing means 23 extracts the name of data from the request for obtaining data. When the request for obtaining data is the request for relaying data, a data requesting means 24 receives data pertinent to the name of the data extracted by the request analyzing means 23 from a data supplying means 12. When the request for obtaining data is the request for relaying data, and a processing to be operated according to the request for obtaining data is not suitable to a history unnecessity condition 22, a history managing means 25 stores the data received by a data requesting means, the name of the data, and the time information of a time when the data relay processing is operated as history information in a history information holding means 21 by making them correspond to each other. An outputting means 26 outputs data to the data using means.