Abstract: In a reflected-light type fluorescence microscope having a turret type filter cassette capable of switching a plurality of excitation filters, a plurality of barrier filters, and a plurality of dichromatic mirrors and selecting a desired set of excitation filter, barrier filter, and dichromatic mirror upon rotation of a turret to perform fluorescence observation of a specimen, the excitation filters, barrier filters, and dichromatic mirrors are directly mounted on the turret. The turret has a shape obtained by cutting the sharp portion of a polyhedral pyramid (for example, octahedral pyramid) having a rotation axis as its central axis along a plane perpendicular to the central axis. The eight equiangular conical surfaces make 45° with the illumination and observation optical axes. Through holes are formed in the 45° conical surfaces to assure an optical path.