To prevent communication data volume from increasing in the case of matching the contents of files among plural file servers with each other and to prevent the load of communication control processing in the file servers and the load of a network from being increased.

Each of terminals 10, 20 transmits a logical record and an updating flag updated by addition/change/deletion at the occurrence of an event. When updating contents respectively received from the terminals 10, 20 are addition, file servers 1, 2 respectively store respective logical records and updating codes in data files 13, 23. In the case of change, the updated logical records are substituted for their corresponding logical records stored in the data files 13, 23 and the updating flags are stored. In the case of deletion, the updating flags are stored in the corresponding logical records in the data files 13, 23. Then only the updated logical records and updating flags stored in the data files 13, 23 are transmitted/received between the file servers 1, 2 through a communication network to execute processing for matching the contents of the data files 13, 23 with each other.