A spectroscopic sensor 1 comprises an interference filter unit 20, having a cavity layer 21 and mirror layers 22, 23 opposing each other through the layer 21, for selectively transmitting therethrough light in a predetermined wavelength range according to an incident position thereof; a light-transmitting substrate 3, arranged on the layer 22 side, for transmitting therethrough light incident on the unit 20; and a light-detecting substrate 4, arranged on the layer 23 side, for detecting the light transmitted through the unit 20. The layer 21 has a filter region 24 held between the layers 22, 23; an annular surrounding region 25 surrounding the region 24 with a predetermined distance therefrom; and an annular connecting region 26 connecting an end part 24e on the substrate 4 side of the region 24 and an end part 25e on the substrate 4 side of the region 25 to each other.