The performances of a semiconductor device are improved. The semiconductor device has a first control gate electrode and a second control gate electrode spaced along the gate length direction, a first cap insulation film formed over the first control gate electrode, and a second cap insulation film formed over the second control gate electrode. Further, the semiconductor device has a first memory gate electrode arranged on the side of the first control gate electrode opposite to the second control gate electrode, and a second memory gate electrode arranged on the side of the second control gate electrode opposite to the first control gate electrode. The end at the top surface of the first cap insulation film on the second control gate electrode side is situated closer to the first memory gate electrode side than the side surface of the first control gate electrode on the second control gate electrode side.