PURPOSE: To transfer the same data at a high speed to plural data processing systems from a main control system by securing the connection between the these processing systems and the main control system via a system bus.

CONSTITUTION: The data processing systems 10-1, 10-2 - 10-n include a system recognition data setting means 16, a system designation data setting means 18, a transfer subject data fetching means 20, and a fetch granting means 22 respectively. The means 22 secures an AND between the system designation data and each system recognition data. Then the fetching of data is granted to each data processing system when the AND is not equal to 0. Furthermore the transfer subject data is fetched by a data processing system having the fetch grant when the data is sent to a system bus via a transfer subject data sending means 28 of a main control system. Thus it is possible to simultaneously transfer the same data to plural data processing systems. As a result, the data transfer speed is increased.