The electronic endoscope 1 includes a distal end portion 11 of the insertion portion 2 of the imaging unit 30 is built, and the first metal frame 20 which holds the viewing window 22, a second metal which holds the objective optical system 32, 34 the frame 33 and 35, a third of the metal frame 36, which is fitted to the rear of the second metal frame 33, 35 to hold the electronic components 42,43,45,46, cloudy to prevent fogging of the observation window 22 and prevention unit 51, by insulating the cloudy and prevention unit 51 and the second metal frame 33 and 35, third made of non-metallic of suppressing the heat transfer generated by the anti-fogging unit 51 to the metal frame 36 heat insulating member 56 If, by comprising a, by suppressing the thermal influence on the solid-state imaging device unit from the anti-fog unit, noise reduction is allowed to have it is possible to acquire a clear image, the clouding of the objective optical system with anti-fog unit efficiency of prevention can be improved.電子内視鏡1は、撮像ユニット30が内蔵された挿入部2の先端部11と、観察窓22を保持する第1の金属枠20と、対物光学系32,34を保持する第2の金属枠33,35と、第2の金属枠33,35の後方に嵌合されて電子部品42,43,45,46を保持する第3の金属枠36と、観察窓22のくもりを防止するくもり防止ユニット51と、くもり防止ユニット51と第2の金属枠33,35とを断熱して、第3の金属枠36へくもり防止ユニット51で発生した熱伝達を抑制する非金属製の断熱部材56と、を具備することで、くもり防止ユニットからの固体撮像素子ユニットへの熱的影響を抑制して、ノイズを低減させてクリアな画像を取得できると共に、くもり防止ユニットによる対物光学系への曇り防止の効率が向上する。
