Imaging optical system, microscope apparatus including the imaging optical system, and stereoscopic microscope apparatus

A stereoscopic microscope apparatus comprising:

• an objective lens;
• a plurality of afocal variable power optical systems that each eject a parallel light ejected substantially parallel to an optical axis of the objective lens from the objective lens to be a plurality of parallel lights;
• and
• a plurality of imaging lenses that collect the parallel lights ejected from the plurality of afocal variable power optical systems, wherein
• at least one of the plurality of afocal variable power optical systems comprises at least two lens groups that move in a direction including a component perpendicular to a reference optical axis of the afocal variable power optical systems at at least part of a section where the magnification is changed from a high-power end state to a low-power end state,
• at least one of the lens groups that move in the direction including the component perpendicular to the reference optical axis of the afocal variable power optical systems is a first correction lens group that moves so that a position of light passing outermost from an optical axis of the objective lens moves toward the optical axis of the objective lens compared with a case of moving in a direction including only a component substantially parallel to the reference optical axis, when the magnification is changed from the high-power end state to the low-power end state, and
• remaining lens groups of the lens groups that move in the direction including the component perpendicular to the reference optical axis of the afocal variable power optical systems is a second correction lens group that corrects the optical paths changed by the first correction lens group.