An integrated circuit device includes: a fin-type active area including a fin top surface on a top portion and an anti-punch-through recess having a lowermost level lower than a level of the fin top surface; a nanosheet stack facing the fin top surface, the nanosheet stack including a plurality of nanosheets having vertical distances different from each other from the fin top surface; a gate structure surrounding each of the plurality of nanosheets; a source/drain region having a side wall facing at least one of the plurality of nanosheets; and an anti-punch-through semiconductor layer including a first portion filling the anti-punch-through recess, and a second portion being in contact with a side wall of a first nanosheet most adjacent to the fin-type active area among the plurality of nanosheets, the anti-punch-through semiconductor layer including a material different from a material of the source/drain region.