1. An apparatus which is provided on a server side on which various data is transmitted to or received from a client, and generates a document representing a Web page screen indicating data provided for the client, comprising: a data object storage unit storing a data object having data to be provided for the client and is provided with an interface representing a data structure of the data; a definition sentence storage unit storing a definition sentence defining a displaying method on the Web page screen about the data of the data object; and a document generation unit generating a document representing a Web page screen on which the data is displayed with the data of the data object associated with the definition sentence based on the interface provided in the data object.