A box-type motor-operated microscope has a motor-operated microscope section having a transmitting illumination optical system, an electric stage, and an image forming optical system; and a housing. The housing includes a fixed housing and a moving housing. The moving housing is movable parallel to an oblique direction with respect to the fixed housing while holding optical elements arranged above the electric stage so that the specimen vessel placed on the electric stage is made replaceable, the motor-operated microscope section is sealed and light-blocked in cooperation with the fixed housing, and the optical axis of the transmitting illumination optical system is practically aligned with that of the image forming optical system.