An ReRAM of the present invention includes a high speed write-in region and a main memory region, only memory cells designated to have the storage state out of the memory cells corresponded to data are set to the storage state in the high speed write-in region. The data written in the memory cell array are transferred to the main memory region, the memory cells of the memory cell array corresponded to the data transferred from the high speed write-in region are reset to the no-storage state in the main memory region, only the memory cells designated to have the storage state out of the memory cells are set, and all memory cells are reset to the no-storage state, or the initial state, in the high speed write-in region.