A memory capable of effectively reducing the chip size not only by sharing a read/write circuit but also by reducing a memory cell size is provided. This memory comprises a first memory cell array having a plurality of first memory cells, a second memory cell array having a plurality of second memory cells different in type from the first memory cells and a selection control circuit provided separately from the first memory cell array and the second memory cell array for controlling selection of either the first memory cell array or the second memory cell array.