In a method of manufacturing a semiconductor integrated circuit device, an active region including a nano-wire may be formed on a bulk insulating layer. A hard mask pattern may be formed to partially expose the nano-wire. A work function-controlling region may be formed on the nano-wire exposed through the hard mask pattern. The hard mask pattern may be removed. A gate insulating layer may be formed on the nano-wire. A gate may be formed to surround the nano-wire.