A metal paste for forming a gas sensor electrode, the metal paste being obtained by dispersing in a solvent: a conductive particle comprising Pt or a Pt alloy and a ceramic powder comprising zirconia or stabilized zirconia, or any of zirconia and stabilized zirconia and additionally one or more oxides of La, Ce, Pr, Nd, Sm, and Hf; the metal paste further comprising: an inorganic oxide particle containing alumina or magnesia and also an insoluble particle that is insoluble in the solvent, wherein the insoluble particle is one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin, and theobromine, or is diamond powder, 0.5 to 3.0 mass% of the inorganic oxide particle is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, 1.0 to 5.0 mass% of the insoluble particle being one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin and theobromine is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle and the insoluble particle, or 1.0 to 15.0 mass% of the insoluble particle being diamond powder is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, and wherein further a particle diameter of the inorganic oxide particle is 5 to 500 nm, a particle diameter of the insoluble particle is 0.5 to 3 μm and a particle diameter of the conductive particle is 5 nm to 2 μm and wherein the dispersed amount of the ceramic powder is 10 to 20 mass% based on the mass of the solid content. a conductive particle comprising Pt or a Pt alloy and a ceramic powder comprising zirconia or stabilized zirconia, or any of zirconia and stabilized zirconia and additionally one or more oxides of La, Ce, Pr, Nd, Sm, and Hf; the metal paste further comprising: an inorganic oxide particle containing alumina or magnesia and also an insoluble particle that is insoluble in the solvent, wherein the insoluble particle is one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin, and theobromine, or is diamond powder, 0.5 to 3.0 mass% of the inorganic oxide particle is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, 1.0 to 5.0 mass% of the insoluble particle being one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin and theobromine is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle and the insoluble particle, or 1.0 to 15.0 mass% of the insoluble particle being diamond powder is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, and wherein further a particle diameter of the inorganic oxide particle is 5 to 500 nm, a particle diameter of the insoluble particle is 0.5 to 3 μm and a particle diameter of the conductive particle is 5 nm to 2 μm and wherein the dispersed amount of the ceramic powder is 10 to 20 mass% based on the mass of the solid content. an inorganic oxide particle containing alumina or magnesia and also an insoluble particle that is insoluble in the solvent, wherein the insoluble particle is one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin, and theobromine, or is diamond powder, 0.5 to 3.0 mass% of the inorganic oxide particle is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, 1.0 to 5.0 mass% of the insoluble particle being one or more kinds of acryl, polyethylene, polyethylene terephthalate, polycarbonate, fluorine resin and theobromine is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle and the insoluble particle, or 1.0 to 15.0 mass% of the insoluble particle being diamond powder is dispersed based on mass of solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle, and wherein further a particle diameter of the inorganic oxide particle is 5 to 500 nm, a particle diameter of the insoluble particle is 0.5 to 3 μm and a particle diameter of the conductive particle is 5 nm to 2 μm and wherein the dispersed amount of the ceramic powder is 10 to 20 mass% based on the mass of the solid content.