An SERS unit includes a support 10 that includes a cavity 11 provided with an opening 12, an optical functional portion 20 that is disposed in the cavity 11 to face the opening 12 and causes surface enhanced Raman scattering, and a package 5 that accommodates the support 10 and is evacuated. The package 5 is in contact with at least an edge 12a of the opening 12, and is bent toward the optical functional portion 20 in a state in which the package 5 is spaced apart from the optical functional portion 20 in the opening 12.