A data sharing method and disk control device are ideal for running applications to process large amounts of data on remote computers in the same manner as in a database system. A disk control device contains a management table for showing the relation between a remote access identifier, a remote disk control device identifier, and command transfer control information for the remote disk control device to the disk identifier used by the host device, When a write command to write data on a designated disk is received from the host computer, the disc controller executes both a write process for writing data on a designated disk and a command transfer process for transferring a write command to the remote disk controller in accordance with command transfer control information in the management table.