An integrated circuit device includes a first fin separation insulating portion over the first device region; a pair of first fin-type active regions apart from each other with the first fin separation insulating portion therebetween and collinearly extending in a first horizontal direction; a first dummy gate structure vertically overlapping the first fin separation insulating portion; a second fin separation insulating portion apart from the first fin separation insulating portion and arranged over the second device region; and a plurality of second fin-type active regions apart from each other with the second fin separation insulating portion therebetween in the second device region and collinearly extending in the first horizontal direction, wherein a vertical level of a lowermost surface of the second fin separation insulating portion is equal to or lower than a vertical level of a lowermost surface of the first fin separation insulating portion.