Provided are: an endoscope comprising a mechanism that makes it possible to easily and accurately center an objective optical system and an imaging optical system and a centering method for the endoscope. The endoscope (1) is provided with: an objective lens (32) that is fixed to an observation window (22) that is provided to a tip section main body (20) an imaging unit (36) that forms an image from light that enters from outside of the tip section main body (20) via the objective lens (32) and causes the result to enter an imaging element (36a) an eccentric ring (40) that is a ring-shaped member having a round outer periphery and that has at least one part of the imaging unit (36) arranged on the inner periphery thereof such that the optical axis of the imaging unit (36) is eccentric with respect to the central axis of the outer periphery and an imaging unit accommodation section (26) that comprises a through hole formed as a long hole shape having a diameter in the minor axis direction that is equal to the outer diameter of the eccentric ring (40), and that is fitted to the eccentric ring (40) by arranging the eccentric ring (40) in the through hole such that the outer peripheral surface of the eccentric ring (40) serves as a mating surface. DRAWING: FIG. 2: AA Observation directionLa présente invention concerne : un endoscope comprenant un mécanisme qui permet de centrer de manière simple et précise un système optique dobjectif et un système optique dimagerie ainsi quune méthode de centrage destinée à lendoscope. Lendoscope (1) comporte : une lentille de focalisation (32) fixée sur une fenêtre dobservation (22) disposée sur un corps principal de section dextrémité (20) une unité dimagerie (36) qui forme une image à partir de la lumière pénétrant depuis lextérieur du corps principal de section dextrémité (20) par lintermédiaire de la lentille de focalisation (32), et délivre le résultat à un élément dimagerie (36a) un anneau excentrique (40) qui est un élément en
