PROBLEM TO BE SOLVED: To provide an imaging optical system which is compact and is capable of acquiring a stereographic image with high resolution and a wide observation view angle, and to provide a stereographic image capturing device and an endoscope having the same.SOLUTION: An imaging optical system includes, in order from the object side to the image side, a front group Gf, comprising a first front group Gf1 centered on a first front group central axis Cf1 and a second front group Gf2 centered on a second front group central axis Cf2 parallel to the first front group central axis Cf1, and a rear group Gb having a single rear group central axis Cb. The first front group Gf1 and the second front group Gf2 of the front group Gf are afocal systems, each comprising at least a negative front first group Gf11, Gf21, a front second group Gf12, Gf22 which is a cemented lens, a front third group Gf13, Gf23 which is a cemented lens, and an aperture stop S1, S2. A first light flux L1 passing through the first front group Gf1 and a second light flux L2 passing through the second front group Gf2 intersect with each other and form an image after exiting the rear group Gb.COPYRIGHT: (C)2014,JPO&INPIT【課題】 小型で高解像な観察画角の広い立体像を得ることが可能な結像光学系、立体撮像装置、及び内視鏡を提供する。【解決手段】 結像光学系は、物体側から像面側へ順に、第1前群中心軸Cf1を中心とする第1前群Gf1及び第1前群中心軸Cf1に並列する第2群中心軸Cf2を中心とする第2前群Gf2を有する前群Gfと、単一の後中心軸Cbを有する後群Gbと、を備え、前群Gfの第1前群Gf1及び第2前群Gb1は、少なくとも、負の前1群Gf11,Gf21と、接合レンズの前2群Gf12,Gf22と、接合レンズの前3群Gf13,Gf23と、開口S1,S2と、からなるアフォーカル系でそれぞれ構成され、第1前群Gf1を通過した第1光束L1及び第2前群Gf2を通過した第2光束L2は、後群Gbを射出後、それぞれ像面Iで交差すると同時に結像することを特徴とする。【選択図】図1
