A data relay device has a reception processing unit for dividing transmitted data into data blocks to store in a storage unit together with labels for managing the data blocks, a manipulation processing unit for manipulating the data blocks stored in the storage unit and a transmission processing unit for transmitting the data blocks of which manipulation is completed to a destination. Since the reception processing unit divides the transmitted data while receiving the same, the reception processing unit, the manipulation processing unit and the transmission processing unit may operated in parallel, thereby realizing reduction of time required to relay the transmitted data.