Patent ID: 8253117

Claim:
A fluorescence detector comprising: a specimen cell for holding a specimen therein; an excitation optical system for irradiating said specimen cell with an excitation light; a fluorescence measurement optical system for detecting the fluorescence that is emitted by the specimen in response to the excitation light; and a fluorescence adjustment optical system comprising a light beam restriction means that is installed close to said specimen cell so as to block the fluorescence that is emitted by the specimen but does not pass through the aperture and having an aperture of a predetermined length in the passage direction of the excitation light in a specimen cell; a condensing means for condensing the fluorescence that passes through the aperture of the light beam restriction means and leading the fluorescence to the fluorescence measurement optical system, said light beam restriction means and said condensing means provided as a pair; and a mechanism for replacing or switching the fluorescence adjustment optical system so that the length of the aperture can be selected from any one of at least 2 types or more.