In order for the salient to face to the 2nd advanced aspect 1s of 1 which, is extended to forward from the 1st advanced aspect 10s of the insertion section and the insertion section and salient 1 the lens paralleling to the peripheral side 1vg of 7 for front observation which is provided and salient, 1 in order for the light absorbent aspect 5j to face, in order the combined use lens 5 which, is provided and, to face to the 1st advanced aspect 10s the lens with the end 5t of advanced side of 12 is provided for 1st front illumination which and combined use lens 5 and the end 12at outside the diameter direction K in the lens 12 for 1st front illumination the hypothetical line which ties to the straight lineIs located Q the illumination light which on, was irradiated from lens 12 for 1st front illumination features that it possesses with the shade section 20m which prevents the fact that entrance light it does on the light absorbent aspect 5j of combined use lens 5.挿入部と、挿入部の第1の先端面10sから前方に突出した突出部1と、突出部1の第2の先端面1sに臨むよう設けられた前方観察用レンズ7と、突出部1の外周側面1vgに沿って受光面5jが臨むよう設けられた兼用レンズ5と、第1の先端面10sに臨むよう設けられた第1の前方照明用レンズ12と、兼用レンズ5の先端側の端部5tと、第1の前方照明用レンズ12における径方向Kの外側の端部12atとを直線に結ぶ仮想線Q上に位置する、第1の前方照明用レンズ12から照射された照明光が兼用レンズ5の受光面5jに入光してしまうのを防止する遮光部20mとを具備していることを特徴とする。
