PROBLEM TO BE SOLVED: To perform measurement in consideration of the point that the state of polarization from a sample changes depending on the irradiation direction of illumination light due to the three-dimensional distribution of birefringence of the sample. An observation device includes a light source unit that irradiates a sample with polarized light, a changing unit that changes an irradiation direction of polarized light with respect to the sample, and a detecting unit that detects at least one of reflected light and scattered light from the sample irradiated with polarized light. And an optical system for forming an image on. [Selection diagram] Figure 1【課題】試料が有する複屈折の３次元的な分布により、照明光の照射方向に応じて試料からの偏光の状態が変化する点を考慮して測定を行う。【解決手段】観察装置は、試料に偏光を照射する光源部と、試料に対する偏光の照射方向を変更する変更部と、偏光が照射された試料からの反射光および散乱光の少なくとも一方を検出部に結像させる光学系と、を備える。【選択図】図１
