Insulated electric wire, wire harness, and insulated electric wire production method

An insulated electric wire comprising:

• a conductor in which a plurality of elemental wires made of a metal material are twisted together;
• an insulation covering that covers an outer circumference of the conductor;
• an exposed portion in which the insulation covering is removed from the outer circumference of the conductor;
• a covered portion in which the insulation covering covers the outer circumference of the conductor, the exposed portion and the covered portion being adjacent to each other in a longitudinal axis direction;
• and
• a water-stopping portion in which a water-stopping agent is over the exposed portion and over a part of the covered portion that is adjacent to the exposed portion;
• wherein
• the water-stopping portion continuously comprises:
• an inter-elemental-wire filling area where the water-stopping agent fills gaps between the elemental wires in the exposed portion,
• an exposed-portion-outer-circumferential area in which the water-stopping agent covers the outer circumference of the conductor in the exposed portion, and
• a covered-portion-outer-circumferential area in which the water-stopping agent covers an outer circumference of the insulation covering in a region that is a part of the covered portion and is adjacent to the exposed portion;
• a subject region is a region of the exposed-portion-outer-circumferential area other than a region closer to the covered-portion-outer-circumferential area which has an increased diameter due to a thickness of the insulation covering;
• a difference between a maximum outer diameter and a minimum outer diameter in the subject region is not greater than 12% of the minimum outer diameter;
• and
• a twist pitch of the elemental wires is smaller in the exposed portion than in an area of the covered portion.