A management device communicable with a plurality of terminals (SD1,... SDn) configured to transmit data, with a plurality of destination devices (ASV1, ASVn, DBSV1, DBSVn) configured to perform respective predetermined processes based on the data transmitted from the terminals, and with a relay device arranged via networks between the terminals and the destination devices, the management device comprising a processor (12, 12A) and a memory (12B, 13) coupled to the processor (12, 12A), wherein the processor (12, 12A) is configured to: receive from the destination devices (ASV1, ASVn, DBSV1, DBSVn) a request regarding data required by individual ones of the destination devices and store the request in the memory (12B, 13); monitor performance of a network between the terminals and the relay device, a load of the relay device or performance of a network between the relay device and the destination devices; based on the request stored in the memory (12B, 13), instruct the relay device regarding an attribute of data to be relayed to the individual ones of the destination devices, the attribute of data comprises a data format, the data format being with respect to a data size; instruct the relay device regarding a scheme of integrating data items to be relayed to an application server (ASV1,..., ASVn) for identifying, sorting and integrating the data items to be relayed, and a scheme of integrating data items to be relayed to a database server (DBSV1,..., DBSVn) for identifying, sorting and integrating the data items to be relayed, the application server (ASV1,..., ASVn) and the database server (DBSV1,..., DBSVn) being destination devices; and based on the result of the monitoring, control the data format for transmitting the data from the terminals to the relay device; wherein the processor (12, 12A) is further configured to: based on the result of the monitoring, generate a control signal to control a frequency of data transmission from the terminals to the relay device and transmit the control signal to the terminals. receive from the destination devices (ASV1, ASVn, DBSV1, DBSVn) a request regarding data required by individual ones of the destination devices and store the request in the memory (12B, 13); monitor performance of a network between the terminals and the relay device, a load of the relay device or performance of a network between the relay device and the destination devices; based on the request stored in the memory (12B, 13), instruct the relay device regarding an attribute of data to be relayed to the individual ones of the destination devices, the attribute of data comprises a data format, the data format being with respect to a data size; instruct the relay device regarding a scheme of integrating data items to be relayed to an application server (ASV1,..., ASVn) for identifying, sorting and integrating the data items to be relayed, and a scheme of integrating data items to be relayed to a database server (DBSV1,..., DBSVn) for identifying, sorting and integrating the data items to be relayed, the application server (ASV1,..., ASVn) and the database server (DBSV1,..., DBSVn) being destination devices; and based on the result of the monitoring, control the data format for transmitting the data from the terminals to the relay device;