A memory mapping unit requests allocation of a remote memory to memory mapping units of other processor nodes via a second communication unit, and requests creation of a mapping connection to a memory-mapping managing unit of a first processor node via the second communication unit. The memory-mapping managing unit creates the mapping connection between a processor node and other processor nodes according to a connection creation request from the memory mapping unit, and then transmits a memory mapping instruction for instructing execution of a memory mapping to the memory mapping unit via a first communication unit of the first processor node.