While assuring the miniaturization of the device, as you suppress the inclination of image of two images which have azimuth difference simply, it makes that you acquire the bright three-dimensional image possible. Being given out from identical subject, opening interval unidirectionally and opening interval to the direction which crosses the luminous flux which possesses the abbreviation parallel two optical axes which it lines up, in parallel direction in order to line up, in order to reduce the interval in the optical axis of two luminous flux which are converted the 1st prism of the pair which it converts (3) and by the said 1st prism (3), it converts, it lines up in the direction where to the 1st prism (3) crosses in parallel direction before the incidence and the 2nd prism of the pair which Out arrays plane of fire the objective optical system for solid photographing which it has (5) it offers (1).装置の小型化を図りつつ、視差のある2つの画像の像の倒れを簡易に抑制するとともに、明るい立体画像を取得することを可能とする。同一の被写体から発せられ、一方向に間隔をあけて並列する略平行な2つの光軸を有する光束を、並列方向に交差する方向に間隔をあけて並列するように変換する一対の第1のプリズム(3)と、該第1のプリズム(3)により変換された2つの光束の光軸の間隔を縮小するように変換し、第1のプリズム(3)への入射前の並列方向に直交する方向に並列して出射面を配列した一対の第2のプリズム(5)とを備える立体撮影用対物光学系(1)を提供する。
