Problem to be solved: to provide a highly reliable endoscope.Solution: the distal end lens 23 inserted into the hole of the frame member 25 made of metal has an optical unit joined to the frame member 25 through a low melting point glass 26 filled in the gap with the frame member 25, and the cross-sectional shape of the tip lens 23 is the first curve 23l1 and the second straight line Having a line portion 23l2, a lens crossing portion 23x of the first curved portion 23l1 and the second straight portion 23l2 is a corner portion, and an opening of the hole of the frame member 25 is a second curved part 25l1, a fourth straight part 25l2 and a connection partThe second curve 25l1 is parallel to the first curve 23l1, the fourth straight portion 25l2 is parallel to the second straight portion 23l2, the connection portion 25l10 is opposed to the lens crossing portion 23x, and the connection cross section 25x1 of the connection portion 25l10 and the fourth straight portion The crossing angle. Theta. 1 is 120 degrees to 180 degrees or less.Diagram【課題】信頼性の高い内視鏡を提供する。【解決手段】金属からなる枠部材25の孔に挿入された先端レンズ23が枠部材25との隙間に充填されている低融点ガラス26を介して枠部材25に接合されている光学ユニットを先端部に有し、先端レンズ23の断面形状が、第1曲線部23L1と第2直線部23L2とを有し、第1曲線部23L1と第2直線部23L2とのレンズ交差部23Xが角部であり、枠部材25の孔の開口が第2曲線部25L1と第4直線部25L2と接続部25L10と、を有し、第2曲線部25L1は第1曲線部23L1と平行であり、第4直線部25L2は第2直線部23L2と平行であり、接続部25L10はレンズ交差部23Xと対向しており、接続部25L10と第4直線部25L2との接続交差部25X1の交差角度θ1が120度以上180度以下である。【選択図】図7
