A scattering medium internal observation apparatus according to the present invention includes: a light source an illuminating apparatus that guides light from the light source to an observation object that is a scattering body and an observation optical system for observing the observation object illuminated by the illuminating apparatus, wherein the illuminating apparatus has a light-guiding member that guides light from the light source to a surface of the observation object, and a light-shielding member that covers the surface of the observation object and which shields light reflected or scattered in the vicinity of the light-guiding member of the observation object is disposed in the vicinity of an end portion of the light-guiding member on an observation object-side.
