Abstract: A data transfer control device comprising an instruction decoding unit for receiving an transfer instruction from an arithmetic processing unit provided in the cluster and decoding the content thereof, some instruction storage units for storing the transfer instruction, a shared memory access unit for reading and writing the data through access to the shared memory provided in the cluster, a data transfer unit for delivering the data read out by the shared memory access unit to the network among clusters, as well as delivering the received data through the network among clusters to the shared memory access unit, and a transfer control unit for controlling the shared memory access control unit and the data transfer unit according to the transfer instruction which is read out from the instruction storage unit, wherein the instruction decoding unit classifies the transfer instruction into an urgent transfer instruction or a non-urgent transfer instruction on the basis of the decoded result thereof, so to store i