A data transfer controller of the present invention can determine whether or not data has been correctly stored in a cache memory even when the data is not transferred to the cache memory in sequential order. Data inputted from a host is transferred to and stored in a prescribed area of the cache memory. First check data is created and stored for each block. A data consistency determination module reads out the data from the cache memory subsequent to the end of a data write, and creates second check data anew. By comparing the second check data against the first check data, it can be determined whether or not the data has been stored normally in the cache memory. The data consistency determination module can also determine the consistency of the data on the basis of the data address written to the cache memory.