The spectrometer 1 is provided with a package 2 in which a light guiding portion 7 is provided, a spectroscopic module 3 accommodated inside the package 2, and a support member 29 arranged on an inner wall plane of the package 2 to support the spectroscopic module 3. The spectroscopic module 3 is provided with a body portion 11 for transmitting light made incident from the light guiding portion 7 and a spectroscopic portion 13 for dispersing light passed through the body portion 11 on a predetermined plane of the body portion 11, and the spectroscopic portion 13 is supported by the support member 29 on the predetermined plane in a state of being spaced away from the inner wall plane.