PURPOSE: To manufacture inexpensively a titled noise filter suitable for mass production by forming in advance a coil and a capacitor in the form of doughnut, inserting them in a magnetic core forming a closed magnetic path of pot shape or the like possible for assembling so as to assemble them.

CONSTITUTION: Two copper or aluminum foils or the like inserted with an insulator such as an insulating sheet like capacitor paper are overlapped, and the overlapped result is wound in the tubular form so as to make a through-hole 8 in its center thereby forming a cylindrical coil in common use with capacitor element 10. A copper wire is wound on the coil in common use with capacitor element 10 at the upper or lower parts, or side by side to form a coil 15 and the coil 15 is connected in series with one strip conductor of the coil in common use with capacitor element 10. Further, an assembly 16 of the coil 15 and the capacitor 10 is fitted to a magnetic core 12 forming a closed magnetic path possible for assembly such as a pot core 11 or an EI core and they are assembled so as to obtain noise filter elements 13 14.