An object is to provide a conductor paste of quality which uses a silver base internal conductor, suppresses the generation of voids and the concomitant occurrence of cracks even when co-fired with ceramic material by the conductor melting method, and has improved productivity, reduced cost, and improved electrical properties. The conductor paste is prepared by dispersing a silver base conductive material and a metal oxide in a vehicle. At least one of Ga oxide, La oxide, Pr oxide, Sm oxide, Eu oxide, Gd oxide, Dy oxide, Er oxide, Tm oxide, and Yb oxide is used as the metal oxide. The conductor paste is fired at a temperature between the melting point and lower than the boiling point of the conductive material.