The invention is applicable to the field of electronic elements and provides a common mode filter, which comprises a first insulation layer, a second insulation layer, a third insulation layer, a fourth insulation layer, a fifth insulation layer, a sixth insulation layer, a first medium layer, a second medium layer, a third medium layer, a fourth medium layer, a first conductor, a spiral second conductor, a spiral third conductor, a fourth conductor, a first lead-out electrode, a second lead-out electrode, a third lead-out electrode and a fourth lead-out electrode, wherein the first conductor and the second conductor form a first coil; the fourth conductor and the third conductor form a third coil; and the magnetic lines of force passing through the first and second coils are parallel to the ground. In the common mode filter of the invention, a medium layer made of a composite material is printed or cast between the first and second coils, so the coefficient of coupling between the electrodes increases; meanwhile, the magnetic lines of force are parallel to the ground, the parasitic capacitance is small, the resonant frequency is improves and the inhibition effect on common mode interference is desirable.