PROBLEM TO BE SOLVED: To provide an endoscope apparatus with a configuration that can conduct at least one of parallel observation and cross-nicol observation easily and reliably.SOLUTION: An endoscope apparatus includes: an insertion part 2 an objective optical system 5 an illumination light emission part 6 an external cylinder 10 a polarization member 100 a first polarization region in the polarization member 100 a second polarization region in the polarization member 100 and a rotation mechanism for causing the external cylinder 10 to be rotatable at the leading end of the insertion part 2 so as to freely switch between a first state in which the light that the first polarization region and the second polarization region transmit is the same polarization, and a second state in which the light that the first polarization region and the second polarization region transmit is the polarization orthogonal to each other, and so as to freely switch among the first state, the second state, and a third state in which the first state and the second state coexist, and regulating a rotational position to a position of the first state, the second state, or the third state.COPYRIGHT: (C)2014,JPO&INPIT【課題】容易かつ確実にパラレル観察とクロスニコル観察との少なくとも一方を行うことができる構成を有する内視鏡装置を提供する。【解決手段】挿入部2と、対物光学系5と、照明光出射部6と、外筒10と、偏光部材100と、偏光部材100における第1の偏光部位と、偏光部材100における第2の偏光部位と、第1の偏光部位と第2の偏光部位とが透過する光が同じ偏光である第1の状態と、第1の偏光部位と第2の偏光部位とが透過する光が直交する偏光である第2の状態との間において切り替え自在となるよう、または、第1の状態もしくは第2の状態と第1の状態及び第2の状態が混在する第3の状態との間において切り替え自在となるよう挿入部2の先端に外筒10を回動自在にするとともに、第1の状態、第2の状態、第3の状態となる位置に回動位置を規定する回動機構と、を具備する。【選択図】図1
