In an MONOS-type memory cell with a split gate structure, short circuit between a selection gate electrode and a memory gate electrode is prevented, and reliability of a semiconductor device is improved. In a MONOS memory having a selection gate electrode and a memory gate electrode that are adjacent to each other and that extend in a first direction, an upper surface of the selection gate electrode in a region except for a shunt portion at an end portion of the selection gate electrode in the first direction is covered with a cap insulating film. The memory gate electrode is terminated on the cap insulating film side with respect to a border between the cap insulating film and an upper surface of the shunt portion exposed from the cap insulating film.