PURPOSE: To provide a very thin inductor having a number of windings relatively easy to adjust and improved inductor characteristics at a low cost, by forming conductor patterns on a substrate with a plated ferrite layer interposed therebetween so that the conductor patterns forms a spiral coil in the lamination direction.

CONSTITUTION: A ferrite layer 2 is deposited over the surface of a substrate 1 by wet plating technique, the substrate being formed of a polyimide film the surface of which has been treated with plasma. A conductor pattern 3 is then formed by the screen printing process using thermosetting silver paste such that one end of the conductor pattern 3 is exposed at the end face A and presents a shape of a partially deficient frame. The conductor pattern 3 is baked at a temperature lower than 150°C. Resist soluble in a solvent is printed on a quarter of the surface located at the lower left-hand corner so that it serves as a mask 4 in the next step for applying a ferrite layer 5. After the ferrite layer 5 is deposited to a thickness of 0.1W10μm, the mask 4 is removed by using a suitable solvent so that a part of the underlying conductor pattern 3 is exposed. An L-shaped conductor pattern 6 is printed so as to be connected with the exposed pattern 3.