Abstract: Disclosed herein is a ceramic thick film circuit substrate for use in an electronic circuit part, characterized in that a conductive layer at a place where it is to be connected with a thick film circuit is composed of a mixture of tungsten and at least one of platinum and palladium. Based on 100 parts by weight of tungsten, platinum is 0.1-100 parts by weight in the case of platinum alone, palladium is 0.1-20 parts by weight in the case of palladium alone; and a total amount of platinum and palladium is 0.1-76 parts by weight in the case of combination of platinum and palladium. Thereby, the ceramic thick film circuit substrate has an excellent oxidation resistance, and low contact resistance to the thick film circuit.