PURPOSE: To facilitate the manufacture of a small sized transformer by a method wherein magnetic substance powder is sintered after applying the magnetic substance powder in spiral shape on a heat-resistant and nonmagnetic substance insulating substrate such as an alumina material and a conductive film is coated on the whole face including the magnetic substance powder for etching and two conductive wires electrically insulated each other are formed on the spiral sintered magnetic substance.

CONSTITUTION: Screen printing is applied with spiral shape to magnetic substance powder paste obtained by mixing magnetic substance powder and a binder on a heat- resistant and non-magnetic substance insulating substance 1 consisting of an alumina material or the like. Next, the magnetic substance powder paste is passed throughin a high-temperature furnace to generate a spiral sintered magnetic substance 2 on the surface of the substrate 1. After that, a copper foil which is a conductive film is coated on the whole face including the spiral sintered magnetic substance 2 for photo etching and two wirings 3 and 4 which are electrically independent from each other are formed on the spiral of the sintered magnetic substance 2. At the same time, terminals 3a and 3b, and 4a and 4b for external connections are provided at both ends of these wirings 3 and 4. This facilitates the manufacture of a small-sized transformer and electrical characteristics are also equalized.