Divided cores 11, 12 includes left and right leg portions and a yoke portion and formed by molding a yoke portion side core material within resin. The leg portions of the divided core are formed by tubular core mounting portions 41, 42. I-shaped leg portion side core materials 51-53 and spacers 6 are mounted in the tubular core mounting portions. A ring-shaped molded core 1 is formed by abutting and integrating the respective leg portions of two divided cores, and a coil 100 is wound around the molded core.