PURPOSE: To eliminate component placing impossibility due to oxidation of the surface of a copper conductor by forming a wiring pattern part of an exposed copper of an air baking material containing Ag.

CONSTITUTION: A component placing pad 2, a base conductor 8 are first formed of an air baking material on a ceramic board 1. Thereafter, a lower conductor 3, a clothe glass 4, an upper conductor 5, a resistor 6 and a protective glass 7 are sequentially printed, and baked to form a pattern, and a conductor part exposed from the glass 7 is formed in an air baking material pattern. With this structure, an improper oxidation of the pad, etc., due to a long stock in the air can be eliminated.