A light-emitting device includes: a substrate having a groove extending in a first direction and a first surface and a second surface respectively arranged to sandwich the groove in a second direction; a first electrode provided on the first surface; a second electrode provided on the second surface; a graphite thin film provided on the first electrode and the second electrode and extending from the first electrode to the second electrode along the second direction in such a way as to be astride the groove; a third electrode provided on the graphite thin film in such a way as to be opposite the first electrode via the graphite thin film; and a fourth electrode provided on the graphite thin film in such a way as to be opposite the second electrode via the graphite thin film.