PROBLEM TO BE SOLVED: To provide a deflection optical system which is an imaging system having a wide angle of view and in which an aberration generated by deflection is excellently corrected and to provide an endoscope including the deflection optical system.SOLUTION: A deflection optical system 1 includes a front lens group Gf having a single optical axis, a rear lens group Gb located on the side opposite to an object with respect to the front lens group Gf, arranged coaxially with the front lens group Gf, and having a single optical axis, a deflection member 2 arranged between the front lens group Gf and the rear lens group Gb and deflecting a luminous flux, and an aperture diaphragm S arranged between the front lens group Gf and the rear lens group Gb.COPYRIGHT: (C)2014,JPO&INPIT【課題】 広画角の撮像系で偏向により発生する収差が良好に補正された偏向光学系及びそれを備えた内視鏡を提供する。【解決手段】 偏向光学系1は、単一の光軸を持つ前レンズ群Gfと、前レンズ群Gfに対して物体とは反対側に位置し、前レンズ群Gfと同軸に配置された単一の光軸を持つ後レンズ群Gbと、前レンズ群Gfと後レンズ群Gbとの間に配置され光束を偏向する偏向部材2と、前レンズ群Gfと後レンズ群Gbとの間に配置された開口絞りSと、を備えることを特徴とする。【選択図】図1
