With the objects of sufficiently reducing the size of a scope while still allowing three-dimensional images to be obtained from two directions, preventing hindering of a surgical procedure or viewing a monitor, and reducing the burden on a surgeon, a surgical observation system includes a first image-acquisition optical system that obtains, from a first observation direction, a pair of optical images, having parallax, of a subject via a pair of apertures disposed side-by-side； and a second image-acquisition optical system that obtains, from a second observation direction in which an angle about an optical axis differs from that of the first observation direction, another pair of optical images, having parallax, of a subject via another pair of apertures disposed side-by-side, wherein the areas of the apertures of the first image-acquisition optical system are larger than the areas of the apertures of the second image-acquisition optical system, and the first image-acquisition optical system and the second image-acquisition optical system are disposed so as the satisfy the following conditional expression: 0.4 ‰¤ L 2 / L 1 ‰¤ 0.6 where L1 is the distance between centers of the apertures of the first image-acquisition optical system, and L2 is the distance between centers of the apertures of the second image-acquisition optical system.
