PURPOSE: To miniaturize a transformer form, and to improve efficiency while facilitating windings by mounting a plurality of endless coil plates with core sections shaping equipping sections for a coil, laminating the coil plates while being set in predetermined plate width and forming the equipping sections for the coil.

CONSTITUTION: With a laminated core 11 in which a plurality of core plates are stacked, central core sections 11a as equipping sections for the core and left and right core sections 11b, 11c are unified at every core plate. The width of the central core section 11a in the core plates superposed at the center is made widest, the width of the central core sections 11a in the core plates stacked in succession is reduced successively, and the central core sections 11a are shaped in a columnar manner. Accordingly, core connecting sections are not affected by magnetic flux, thus improving precision while facilitating windings.