A spectrometer includes a first spectroscopic unit and a second spectroscopic unit. A light passing part, a reflection part, a common reflection part, a dispersive part, and a light detection part included in the first spectroscopic unit are arranged along a first reference line when viewed in a Z-axis direction. A light passing part, a reflection part, the common reflection part, a dispersive part, and a light detection part included in the second spectroscopic unit are arranged along a second reference line when viewed in the Z-axis direction. The first reference line and the second reference line intersect with one another.