Abstract: To provide a gas sensor with fast response and high sensitivity to oxygen gas. Disclosed is a gas sensor 100 including: a substrate 10; a first pad electrode 12A and a second pad electrode 12B; a nanowire 14 made of a specific metal; and an oxide layer 16 made of a high-resistance semiconductor that is an oxide of a metal different from a metal constituting the nanowire 14. The first pad electrode 12A and the second pad electrode 12B are formed on or above the substrate 10. The nanowire 14 connects the first pad electrode 12A and the second pad electrode 12B and is formed on or above the substrate 10. The oxide layer 16 is formed in contact with the nanowire 14. This contact between the nanowire 14 and the oxide layer 16 provides fast response and high sensitivity to oxygen gas.

Abstract: A nanopore structure in an embodiment according to the present invention includes a first metal member having a thin film structure and a through hole, and a second metal member arranged to narrow a diameter of the through hole. The first metal member and the second metal member form a nanopore having a pore diameter of 10 nm or less.