An integrated circuit device includes an embedded insulation layer, a semiconductor layer on the embedded insulation layer, the semiconductor layer having a main surface, and a plurality of fin-type active areas protruding from the main surface to extend in a first horizontal direction and in parallel with one another, a separation insulation layer separating the semiconductor layer into at least two element regions adjacent to each other in a second horizontal direction intersecting the first horizontal direction, source/drain regions on the plurality of fin-type active areas, a first conductive plug on and electrically connected to the source/drain regions, a buried rail electrically connected to the first conductive plug while penetrating through the separation insulation layer and the semiconductor layer, and a power delivery structure arranged in the embedded insulation layer, the power delivery structure being in contact with and electrically connected to the buried rail.