PURPOSE: To contrive to prevent the generation of beat noise, to stabilize welding stress, to simplify controlling welding electrode and to improve production efficiency by a method wherein welding junction is performed to a laminated core body with a concave section of a junction aperture provided wavily by a concave section and a convex section at right angle to direction of lamination placed on a mounting plate.

CONSTITUTION: The laminated core body of the titled apparatus main body 11 is possessed with an E type laminated core 14 and an I type core 16, and the primary coil 17, the second coil 18 and a pass core 19 are inserted to the E type laminated core 14, thereafter the titled apparatus is composed with the I type laminated core 16 performing welding junction. A pair of junction apertures 25, in which a concave section 26 and a convex section 27 are provided wavily at a right angle to direction of lamination inside of the both edge sections 21a of a mounting plate 21, are formed at the center of a mounting aperture 22. At least welding junction is performed to each convex section 27 with the mounting plate 21. Thereby, preventing heat noise from generating, stabilizing welding stress and improving production efficiency can be contrived. Moreover, as a welding electrode is welded mutually with the convex section 27 along to the welding aperture 25, the control of arrangement positioning a welding electrode and the like is simplified.