The performances of a semiconductor device are improved. Between a memory gate electrode and a p type well, and between a control gate electrode and the memory gate electrode of a split gate type nonvolatile memory, an insulation film having a charge accumulation layer therein is formed. The insulation film includes a lamination film of a silicon oxide film, a silicon nitride film formed thereover, another silicon oxide film formed thereover, and an insulation film formed thereover, and thinner than the upper silicon oxide film. The insulation film is in contact with the memory gate electrode including polysilicon. The insulation film is formed of a metal compound containing at least one of Hf, Zr, Al, Ta, and La, and hence can cause Fermi pinning, and has a high dielectric constant.