Abstract: A stereoscopic-vision endoscope having an objective optical system consisting of a front optical system having a single optical axis including a field conversion optical system, and a rear optical system including optical systems that have a plurality of optical axes. A light beam is received from the front optical system so as to form images on the optical axes, and thus form a plurality of images. The front and rear optical systems can be turned relative to each other. Thus, a magnitude of parallax permitting a sufficient sense of three-dimensionality can be provided, and the postures of images can be corrected responsively to a change in direction of view resulting from the rotation of an insertional part.