A semiconductor device includes active patterns disposed on a substrate and including central portions, respectively, bit lines extending in a first direction on the central portions of the active patterns, word lines intersecting the active patterns in a second direction intersecting the first direction, fence patterns disposed between the bit lines adjacent to each other on the word lines, a contact trench region intersecting the active patterns and the word lines in a third direction intersecting the first and second directions, and bit line contacts and filling insulation patterns alternately arranged in the third direction in the contact trench region. The first to third directions are parallel to a bottom surface of the substrate. The filling insulation patterns are disposed between the word lines and the fence patterns, respectively.