PURPOSE: To enable detection with high sensitivity, by forming an org. polymer, wherein a plurality of rings selected from benzene or a derivative thereof are bonded through chalcogen atoms or chalcogen atom-containing atomic groups in a chain form, between a pair of electrodes.

CONSTITUTION: A support plate 1 comprises an insulating material such as glass, ceramic or Teflon and is formed in a comb like shape such that a pair of electrodes 2A, 2B are mutually engaged with the support plate 1. For example, electrodes 2A, 2B are formed by the vapor deposition of Au and a gas response film (org. polymer) 3 is formed so as to be interposed between the electrodes 2A, 2B. As the org. polymer, there is a compound wherein phenylene units are bonded through an ether or sulfide bond and the gas response film is formed by the melt molding or hot press of the film like or fibrous org. polymer. When decomposed gas is generated in the gas response film 3 comprising the org. polymer, said decomposed gas is diffused throughout the response film 3 and the change in conductivity is generated and, by detecting the change in the resistance value between the electrodes 2A, 2B, the variation in the gaseous atmosphere can be detected.