A semiconductor device includes a substrate with an upper surface and a lower surface, and first to third active patterns extending from the upper surface of the substrate. The first to third active patterns are arranged adjacent to each other in a first direction. The second active pattern is disposed between the first and third active patterns. The semiconductor device also includes a first gate electrode surrounding side surfaces of the first and second active patterns, and a second gate electrode surrounding side surfaces of the third active pattern. Each of the first to third active patterns includes a first impurity region, a channel region, and a second impurity region.