PROBLEM TO BE SOLVED: To provide a flexible tube of an endoscope capable of maintaining an initial insertion property seldom causing change in flexibility of an outer cover so much over a long period of time even when receiving heat loads by sterilization after the endoscope is used.SOLUTION: An outer cover 14 is formed by piling up a synthetic resin material 114A of a characteristic to be harder than before a heat load is received after the heat load is received and the heat load is removed and a synthetic resin material 114B of a characteristic to be softer in multiple layers, or by blending such two or more kinds of synthetic resin materials 114A and 114B.COPYRIGHT: (C)2013,JPO&INPIT【課題】内視鏡使用後の滅菌消毒等で熱負荷を受けても、長期にわたって外皮の可撓性がさほど変化せず、当初の挿入性を維持することができる内視鏡の可撓管を提供すること【解決手段】外皮14が、熱負荷を受けてからその熱負荷が除去された後において、熱負荷を受ける前よりも硬化する特性の合成樹脂材114Aと、軟化する特性の合成樹脂材114Bとを複数層に重ね合わせて、又はそのような複数種類の合成樹脂材114A,114Bをブレンドして形成されている。【選択図】 図2
