To provide an enlargement observation device that can perform a normal Differential Interference Contrast (DIC) observation and a DIC observation having impacts of a flare reduced.SOLUTION: An enlargement observation device comprises: a polarizer that, of illumination light a light source irradiates, makes only a polarization component along a transmission axis transmit; a differential interference prizm of which a fast axis and slow axis form 45 degrees respectively, and is movable in a direction orthogonal to an optical axis; an analyzer that is arranged in a crossed Nicol configuration with respect to he polarizer, and, of reflection light, makes only a polarization component along the transmission axis transmits; an acquisition unit that acquires objective lens information for identifying which objective lens of a first objective lens and a second objective lens is arranged on the optical axis; and a display control unit that makes a display unit display a retardation position of the first objective lens or the second objective lens in accordance with the objective lens information.SELECTED DRAWING: Figure 1
展开▼