An endoscope is provided that obtains a favorable field of view. The endoscope includes: an illumination optical system that has an illumination window protruding from an end surface of an insertion unit； a cylindrical body that protrudes from the end surface； and an observation window that is arranged inside the cylindrical body and protrudes from the end surface, in which the illumination window and the observation window satisfy Formulas (1) and (2), and an intersection between a straight line, which connects an edge of a light incident surface of the observation window and an edge of an end surface of the cylindrical body, and an optical axis of the illumination optical system is located to be closer to the insertion unit than the end surface of the insertion unit.C≥；D ； ；(1)E≥；D ； ；(2).
