PURPOSE: To remarkably enhance electric characteristic and manufacture an insulated electric wire without any fray generated in a cut portion by winding a synthetic resin insulating tape around a conductor desired times in coexistence of a soluble solvent, and tightly bonding insulating tapes to each other so as to form an insulating layer.

CONSTITUTION: While a straight conductor 1 of, for example, 2.0×10.0mm is being traveled at a predetermined speed, an Aramid paper tape 2 having a given thickness is wound around the conductor, and then, the conductor is passed through a solvent coating device 3 full of dimethylformamide. The tape is coated with dimethylformamide to be fitted to dimethylformamide, before being pressed by a heating roll 4 with application of heat so that a solvent contained in the Aramide paper tape is evaporated and dried, and consequently, the tapes are bonded to each other, thus obtaining an insulated electric wire. Therefore, an electric property can be remarkably improved, and furthermore, a connecting operation can be facilitated without any fray generated in a cut portion.