A semiconductor device includes a fin type pattern extending in a first direction on a substrate, a first gate electrode extending in a second direction intersecting the first direction on the fin type pattern, a source/drain region on a side wall of the first gate electrode and in the fin type pattern, a separation structure extending in the first direction on the substrate, the separation structure including a first trench and being spaced apart from the fin type pattern and separating the first gate electrode, an interlayer insulating layer on a side wall of the separation structure and covering the source/drain region, the interlayer insulating layer including a second trench having a lower surface lower than a lower surface of the first trench, and a contact connected to the source/drain region and filling the first trench and the second trench.