Provided are an endoscope leading end structure wherein a lens can be bonded and fixed with predetermined reliability even if the structure has a reduced diameter, and a method for assembling the structure. An endoscope leading end structure (1) is provided with a lens (10), an image pickup unit (30) or an imaging fiber (40), and a cylindrical body (20). The cylindrical body has a first inner circumferential surface (21) that holds the outer circumferential surface (14) of the lens, and a second inner circumferential surface (22) that holds the outer circumferential surface of the image pickup unit or that of the imaging fiber. The leading end of the image pickup unit or that of the imaging fiber is locked by being in contact with a step surface (23) formed at a connecting portion (D) between the first inner circumferential surface and the second inner circumferential surface. The inner surface of a leading end portion (25) is provided with a leading end circumferential contact portion (25b) that is in contact with the whole circumference of the leading end surface (13) outside of the effective diameter of the lens, a circumferential direction path (29a) is formed by means of a groove (25c) and the like, and a vertical groove (24) is formed, said vertical groove communicating with the circumferential direction path from the step surface. An adhesive applied to the vertical groove, the circumferential direction path and between the outer circumferential surface of the lens and the first inner circumferential surface is hardened, and the lens is bonded.Cette invention concerne une structure terminale dirigeant un endoscope dans laquelle une lentille peut être collée et fixée avec une fiabilité prédéfinie même si la structure a un diamètre réduit. Linvention concerne également une méthode dassemblage de la structure. La structure terminale dirigeant lendoscope (1) est équipée dune lentille (10), dune unité de récupération dimage (30) ou dune fibre pour prise dimage (40
