An optical module includes at least a carrying stage, at least an actuator unit and at least an optical assembly. The carrying stage has a first aperture. The actuator unit is disposed at one side of the carrying stage and has a second aperture. The optical assembly is connected with the actuator unit, and the actuator unit adjusts the position of the optical assembly. A radiated wave enters from one side of the optical module and passes through the first aperture, the second aperture and the optical assembly. A microscope with the optical module has compact size and is easily assembled and carried. The optical module and microscope can efficiently reduce the effect of ambient temperature variations so as to improve the measuring stability thereof.