To provide the motor-driven revolver which is almost as large as a manual revolver without spoiling the strength of a microscope main body and operability for an objective lens.

The motor-driven revolver 10 is equipped with a fixation part 20 which is attachable to and detachable from the fitting surface (b) of the microscope main body and a rotation part 30 which can be rotatable about the fixation part 20 and mounted with objectives; and the rotation part 30 is mounted on the fixation part 20 obliquely to the fitting surface (b) and the fixation part 20 is equipped with a motor 40 which rotates the rotation part 30 in the space formed between the rotation part 30 and fitting surface (b) because of the tilt of the rotation part 30.