A memory includes a nonvolatile memory cell array, and a memory control circuit which carries out writing of data to and reading of data from the memory cell array in access units of N bits where N is an integer equal to 2 or greater. The memory cell array includes a rewritable area in which both writing of data and reading of data are permissible, and a read-only area in which writing of data is prohibited and reading of data is permissible. The rewritable area is configured so that the N bits constituting one access unit contain both actual data and an error detection code. The read-only area is divided between an actual data area in which the N bits constituting one access unit contain actual data, and an error detection code area in which the N bits constituting one access unit contain error detection codes.