To save any system resource such as a CPU and a memory, and to dispense with any means for previously knowing the file size of a file to be transferred in file transfer.

A file transferring means 12 transfers a file 15 to be transferred to a transfer destination computer 20. When the transfer is completed, a file erasing means 13 erases a flag file 26 of the transfer destination computer 20. In the transfer destination computer 20, the flag file 26 is checked at fixed time intervals by a monitoring means 22. When it is detected that any flag file 26 is not present, that is, it is detected that the flag file 26 is erased as the checked result, it is recognized that the file transfer is completed, and a transfer file using program 27 is started.