SPECTROMETER

A spectrometer 1A comprises a package 2 having a stem 4 and a cap 5, an optical unit 10A arranged on the stem 4, and a lead pin 3 penetrating through the stem 4. The optical unit 10A has a dispersive part 21 for dispersing and reflecting light entering from a light entrance part 6 of the cap 5, a light detection element 30 for detecting the light dispersed and reflected by the dispersive part 21, a support 40 for supporting the light detection element 30 such as to form a space between the dispersive part 21 and the light detection element 30, a projection 11 projecting from the support 40, and a wiring electrically connected to the light detection element 30. The projection 11 is arranged at such a position as to be separated from the stem 4. The lead pin 3 is electrically connected to the second terminal part while being disposed to the projection 11.