Each of a plurality of storage devices (N-1 to N-n) has a plurality of memory blocks for storing data. A data writing apparatus obtains error information which represents good blocks which can store data correctly, from the plurality of storage devices (N-1 to N-n). The data writing apparatus determines a memory block in which data is to be written, in each of the plurality of storage devices (N-1 to N-n), based on the obtained error information. The data writing apparatus controls the plurality of storage devices (N-1 to N-n), and writes predetermined data in the determined memory blocks.