A light detection device of the present invention includes: a wiring board; a first support part disposed on a mounting surface of the wiring board; a Fabry-Perot interference filter having a first mirror part and a second mirror part between which a distance is variable and having an outer edge portion disposed in a first support region of the first support part; a light detector disposed on the mounting surface to face the first mirror part and the second mirror part on one side of the first support part; and a temperature detector disposed on the mounting surface, wherein the temperature detector is disposed on the mounting surface such that at least a part of the temperature detector overlaps a part of the Fabry-Perot interference filter when seen in a first direction perpendicular to the mounting surface and such that at least a part of the temperature detector overlaps a part of the first support part when seen in a second direction in which the first support part and the light detector are aligned with each other, and wherein a first distance between the temperature detector and the first support part in the second direction is smaller than a first width of the first support region in the second direction.