Insulated electric wire and wire harness

An insulated electric wire comprising:

• a conductor in which a plurality of elemental wires made of a metal material are twisted together;
• and
• an insulation covering that covers an outer circumference of the conductor;
• wherein the insulated electric wire further comprises:
• an exposed portion in which the insulation covering is removed from the outer surface of the conductor;
• and
• a first covered portion and a second covered portion in which the insulation covering covers the outer circumference of the conductor,
• the first covered portion, the exposed portion, and the second covered portion being adjacent to each other in a direction of a longitudinal axis of the insulated electric wire in this order,
• a water-stopping portion being further provided in at least an area extending from a part of the exposed portion to a part of the first covered portion, gaps between the elemental wires in the water-stopping portion being filled with a water-stopping agent, and
• a region of the second covered portion that is adjacent to the exposed portion being a non-waterproof end that has a void between the conductor and the insulation covering, wherein
• in the second covered portion, an outer diameter of the conductor is smaller in an area of the non-waterproof end adjacent to the exposed portion than in a remote area that is distanced from the exposed portion.