Patent ID: 7286225

Claim:
A spectroscope comprising: an optical fiber on which light is incident; a collimator optical system that collimates the light come out from the optical fiber; a spectroscopic element that disperses the light collimated by the collimator optical system; a detector that is composed of a plurality of detector elements disposed at least in a direction of dispersion and that detects the light dispersed by the spectroscopic element; and a focusing optical system that focuses signal light from the spectroscopic element onto a detecting surface of the detector, wherein the following conditional expression is satisfied: NA fiber≦ NAf ×( ff/fc ) where NAfiber denotes a numerical aperture of the optical fiber, NAf denotes a numerical aperture of the focusing optical system, ff denotes a focal length of the focusing optical system, and fc denotes a focal length of the collimator optical system.