A storage technology for improving reliability in writing host data to a storage device is provided. A first check code based on write data is stored in cache memory 370, and storage section 50 is instructed to write, in specified predetermined storage area, write data with the first check code appended thereto, after which the storage section 50 is instructed to read data stored in said predetermined storage area; a second check code is generated on the basis of the read data, and in the event that the correspondence relationship between the first and second check codes is correct, it is decided that the write data was written normally to the storage section 50.