A memory cell of a nonvolatile memory and a capacitive element are formed over the same semiconductor substrate. The memory cell includes a control gate electrode formed over the semiconductor substrate via a first insulating film, a memory gate electrode formed adjacent to the control gate electrode over the semiconductor substrate via a second insulating film, and the second insulating film having therein a charge storing portion. The capacitive element includes a lower electrode formed of the same layer of a silicon film as the control gate electrode, a capacity insulating film formed of the same insulating film as the second insulating film, and an upper electrode formed of the same layer of a silicon film as the memory gate electrode. The concentration of impurities of the upper electrode is higher than that of the memory gate electrode.