An apparatus for fluorescence observation includes an excitation filter which transmits only exciting light of an specific wavelength among illumination light, and an absorption filter which blocks 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 1 nm to 6 nm, and change of the half-value wavelength of the excitation filter and the absorption filter when humidity changes from 10% to 95%, is 0.5 nm or less.