A coherency control system includes a logical-physical address translation unit which translates a logical address including a first tag and an index address into a physical address including a second tag and the index address. The system includes a request output unit which transmits a load request. The system includes a corresponding state storage unit storing a relation state between areas of two storage apparatuses based on the way number included in the load request and the second tag and the index address of the physical address also included in the load request. The system includes an invalidation instructing unit which transmits an invalidation instruction including the index address and the way number based on the second tag of the physical address included in the store request and the relation state stored in the corresponding state storage unit.