The degree of integration and the number of rewriting of a semiconductor device having a nonvolatile memory element are improved. A first MONOS nonvolatile-memory-element and a second MONOS nonvolatile-memory-element having a large gate width compared with the first MONOS nonvolatile-memory-element are mounted together on the same substrate, and the first MONOS nonvolatile-memory-element is used for storing program data which is scarcely rewritten, and the second MONOS nonvolatile-memory-element is used for storing processed data which is frequently rewritten.