To increase the connecting strength of a wire and a metal fitting by interposing hard powder between a receiving hole for a terminal metal fitting and an inner wire inserted therein.

The end part of an inner wire 12 is inserted in abrasive grains in a container to make the abrasive grains thinly adhere to the outer periphery. Subsequently, when the end part is inserted in a receiving hole 21 of a terminal metal fitting 20, the abrasive grains easily enter the projected and recessed parts of the surface because the wire 12 is a stranded wire, so that insertion is smooth and abrasive grains enter the hole 21 accompanied. Subsequently, a clamping part 24 is put between a lower mold 26 and an upper mold 27 having a V-groove with an included angle of 90°, a cylindrical section of the clamping part 24 is a substantially square, and the inner surface of the clamping part 24 abuts on the outer surface of the wire 12 to be deformed to a little recessed position. Thus, the outer surface of the wire 12 and the inner surface of the clamping part 24 come into contact with each other at a wider area, so that both surfaces are strongly connected by residual stress produced by clamping. At this time, the abrasive grains are harder than the outer surface of the wire 12 and the inner surface of the clamping part 24, so that the abrasive grains are forced into the surfaces to wedge both surfaces. Thus, high pulling strength can be obtained.