Information system and data access method

A data access method in an information system including a plurality of data utilization systems connected to a network N, and a plurality of data provision systems connected to a network, wherein a data utilization system transmits a request for utilizing data in a data provision system to another data utilization system Pthrough the network N, the data utilization system, upon receipt of the data utilization request, transmits a processing execution request corresponding to the data utilization request to the data provision system through the network N, the data provision system, upon receipt of the execution request, executes processing corresponding to this execution request and transmits necessary data to the data provision system through the network, and the data provision system receives the data and stores the same.