An integrated inductor apparatus integrated to be a plurality of inductors is provided. The integrated inductor apparatus includes inductor windings to form inductors and includes at least two windows each having at least one of the inductor windings disposed therein and magnetic core units, each having a closed geometrical structure to form one of the at least two windows, wherein two of the neighboring magnetic core units have a shared magnetic core part. The magnetic core units comprise at least two kinds of material having different magnetic permeability corresponding to different sections of the magnetic core units, wherein the reluctance of the shared magnetic core part is smaller than the reluctance of a non-shared magnetic core part of the magnetic core units.