An integrated circuit device including a lower electrode on a substrate, the lower electrode including a first lower electrode portion extending in a first direction perpendicular to a top surface of the substrate and including a first main region and a first top region, and a second lower electrode portion extending in the first direction on the first lower electrode portion and including a second main region and a second top region; a first top supporting pattern surrounding at least a portion of a side wall of the first top region of the first lower electrode portion; and a second top supporting pattern surrounding at least a portion of a side wall of the second top region of the second lower electrode portion, and the second lower electrode portion includes a protrusion protruding outward to the second top supporting pattern.