the present invention relates to a semiconductor device including an insulated - gate field effect transistor having a contact hole formed in an inter - layer insulating film on an s / d region adjacent to a gate electrode and has an object to provide a semiconductor device capable of securing the uniformity of the thickness of an insulating film between a gate electrode and an s / d electrode or interconnection layer while integrating elements at a high density . the semiconductor device comprises an s / d region formed in a semiconductor layer at the both sides of the gate electrode , an insulating side wall formed on side surface of the gate electrode , a conducting side wall covering side surface of the insulating side wall and contacting the s / d region , a covering insulating film for covering the gate electrode , s / d region , insulating side wall , and conducting side wall , and a contact hole formed in the covering insulating film on the s / d region of at least one side .