A semiconductor device includes a first multi-channel active pattern, a field insulation layer disposed on the first multi-channel active pattern and including a first region and a second region, the first region having a top surface protruding from a top surface of the second region to a top surface of the first multi-channel active pattern, a first gate electrode crossing the first multi-channel active pattern, the first gate electrode being disposed on the field insulation layer, and a first source or drain disposed between the first gate electrode and the first region of the field insulation layer and including a first facet, the first facet being disposed adjacent to the first region of the field insulation layer at a point lower than the top surface of the first multi-channel active pattern.