A storage system is able to perform an operation of remote copy from a first storage apparatus to a second storage apparatus. A first control unit transfers summary information of copy target data stored in the first storage apparatus from the first storage apparatus to the second storage apparatus. A second control unit checks the summary information against information stored in the second storage apparatus. The second control unit transfers the checked result from the second storage apparatus to the first storage apparatus. If the checked result indicates matching discrepancy, the first control unit transfers the copy target data to the second storage apparatus and completes the remote copy operation.