A semiconductor device is disclosed. The semiconductor device may include a semiconductor substrate including a protruding active pattern, a first gate pattern provided on the active pattern and extended to cross the active pattern, a first capping pattern provided on a top surface of the first gate pattern, the first capping pattern having a top surface, a side surface, and a rounded edge, and a first insulating pattern covering the side surface and the edge of the first capping pattern. A thickness of the first insulating pattern on the edge of the first capping pattern is different from a thickness of the first insulating pattern on outer side surfaces of the spacer patterns.