There is provided a detection system capable of simultaneously detecting a plurality of fluorescences or phosphorescences having different dominant wavelengths generated from a minute region and a probe therefor. A fluorescence detection system includes a probe having a lens and optical fibers and arranged on one end thereof. The probe receives excitation light with a dominant wavelength and excitation light with a dominant wavelength at one end of the lens and converges the excitation lights at the solution containing Cy3 and Cy5 in a channel inside a microchemical chip and the probe receives fluorescence with a dominant wavelength and fluorescence with a dominant wavelength at the other end of the lens and converges the fluorescences at the tips of the optical fibers.