An apparatus for fluorescence observation comprises an excitation filter (33) which transmits only exciting light of a specific wavelength among illumination light, and an absorption filter (41) which interrupts the exciting light and transmits only fluorescence generated from a specimen when the exciting light is irradiated to the.specimen. Here, an interval of a half-value wavelength at a long-wavelength side of the excitation filter and a half-value wavelength at a short-wavelength side of the absorption filter is in a width between Inm to 6nm, and change of the half-value wavelength of the excitation filter and the absorption filter when humidity changes from 10% to 95%, is 0.5nm or less.
