A compensation optical apparatus for obtaining and image of an object without reduction in image quality irrespective of aberration compensation, includes: a division unit for dividing a return beam from a measured object an aberration measurement unit for measuring an aberration caused by the measured object, with a divided beam from the division unit an aberration compensation unit for performing aberration compensation based on the aberration measured by the aberration measurement unit a projection unit for projecting a beam obtained by the aberration compensation in the aberration compensation unit to the measured object an acquirement unit for acquiring a value exhibiting a state of the measured object based on the return beam from the measured object, which is obtained by the beam projected from the projection unit and a control unit for retreating the division unit from an optical path based on the value acquired by the acquirement unit.
