When forming molded resin on a terminal-equipped conductive wire, cases where resin inside the mold for insert-molding leaks out from the mold are suppressed. A smooth portion having a smooth outer circumferential surface is formed in a conductive wire of a terminal-equipped conductive wire (smooth portion formation step (S2)). Furthermore, a molded resin member that covers the terminal connection portion is formed in a state where the terminal connection portion provided is inserted into an insert-molding mold, and a portion of the conductive wire that extends from a metal terminal is exposed to the outside through an opening portion of the mold (insert-molding step (S3)). The outer shape of the smooth portion is a shape that corresponds to the opening shape of the opening portion of the mold. In the insert-molding step (S3), the interior of the mold is filled with a resin in a state where the inner circumferential surface of the opening portion of the mold is in contact with the outer circumferential surface of the smooth portion.