A data processing device includes: an FPGA that includes a plurality of core circuits to which a data processing function is settable through a program file, and processes input data through the core circuits; an FPGA circuit file storage unit that stores the program file; and a control unit that sets the data processing function to the core circuits. In the data processing device, a request including information specifying the data processing function to be set and the core circuit is transmitted to a file management server, the data processing function is set based on a program file received in response to the request, and the received program file is stored in the FPGA circuit file storage unit.