PURPOSE: To enhance the quality and productivity by pressing the C-shaped laminate core of a coil part, coupled such that the outer face side of winding is pressed against the inner face side of the C-shaped laminate core with respect to an I-shaped laminate core, on the back of the tapered face ' and then welding the tapered face of C-shaped laminate core at the tip end.

CONSTITUTION: Winding grooves 3 having a flange 2 are made at the opposite ends of a bobbin 1 and a winding 4 is set therein. An I-shaped laminate core 6 tapered 5 at the opposite ends is laminated and inserted into the central hole 7 of the bobbin 1. A pair of C-shaped laminate cores 9 having opposite tapered 8 leg parts, to be abutted against the tapered ends of the I-shaped laminate core 6, is then assembled from the upper surface of winding 4. Subsequently, the C-shaped laminate core 9 is pressed, on the back 10a of the tapered part 8, by means of protrusions 18a at the opposite ends of a press jig 18 having recessed forward end thus eliminating the gap between the tapered parts 5 and 8 of the I-shaped laminate core 6 and the C-shaped laminate core 9. Finally, the C-shaped laminate cores 9 are welded at the abutted points.