A gas sensor device includes: a pair of electrodes; a conductor that electrically connects the pair of electrodes to each other; and at least one of a thiolate anion and an organic compound having a mercapto group, which is disposed on a surface of the conductor. A gas evaluation apparatus includes a first gas sensor device as described above and a second gas sensor device which has neither the mercapto group nor the thiolate anion disposed on a surface of its conductor.