1. A storage control system for controlling the storage of data in storage devices, comprising: a plurality of storage devices for storing data; a storage device control section for controlling the storage of received data in said plurality of storage devices; a connecting section connected to said storage device control section; a first channel control section connected to at least one of a local area network and a storage area network located externally to said storage control system, and to said connecting section; a second channel control section for transferring data sent from said first channel control section via said connecting section, to an external storage control system, via the same storage network as said storage network, or a separate storage network to same; a shared memory wherein first control information exchanged by said first channel control section, said second channel control section, and said storage device control section, is stored; and a cache memory for temporarily saving data exchanged between said first channel control section or said second channel control section and said storage device control section; wherein said first channel control section comprises a second processor for receiving block level data from a first processor which converts file level data received via said local area network into said block level data; at least one of said first processor and said second processor judges whether all or a portion of said block level data is to be stored in either said storage control system or said external storage control system, on the basis of second control information indicating whether said data is to be stored in either said storage control system or said external storage control system; and said second processor transfers said block-level data received from said first processor, to at least one of said storage device control section and said second channel control section, on the basis of the result of said judgment.