To provide a surgical microscope illumination structure capable of preventing reflection generated when illumination light is transmitted through a cover glass from adversely affecting expected observation performance.SOLUTION: Even though a part of illumination light (A) is reflected from a surface of a cover glass 10, reflected components (a) are directed in a directions off a mirror 12 to prevent the reflected components (a) from reaching the mirror 12 and entering an observation optical system together with rays (L) from a surgical field (G). Accordingly, expected observation performance is not adversely affected.SELECTED DRAWING: Figure 4【課題】照明光がカバーガラスを透過する際の反射光成分が本来の観察性能に悪影響を与えない手術顕微鏡の照明構造を提供する。【解決手段】照明光Ａの一部がカバーガラス１０の表面で反射されても、その反射光成分ａがミラー１２を外れた方向へ指向するため、反射光成分ａがミラー１２に当たることはなく、それが術野Ｇからの光束Ｌと一緒に観察用の光学系に導入されることがない。従って本来の観察性能に悪影響を与えることはない。【選択図】 図４
