Production method of gas sensor

To provide a method for producing a sensing film for gas sensors by sintering particles comprising a metal or a metal oxide on a substrate, where the sensing film for gas sensors having excellent sensor properties such as sensitivity and responsibility can be easily and simply formed. A nano-meter order particle, a dispersant for preventing aggregation of the particles, and a scavenger for trapping the dispersant at the sintering are mixed in a solvent to prepare a paste body, and this paste body is coated on a base material and fired, thereby forming a sensing film.