Provided is an endoscope that is capable of improving the ease of insertion by reducing the size of a distal end of an inserted portion, while ensuring a preferable observation field of view by improving the light distribution of illumination light. The endoscope employed has a tube-like inserted portion having a distal end a light guide that is accommodated in the inserted portion and guides illumination light to the distal end an illumination optical system that radiates the illumination light guided by the light guiding member and an objective optical system that collects light from a region illuminated by the illumination optical system, which are disposed at the distal end of the inserted portion, wherein an end portion of the light guide facing the plano-concave lens extends substantially parallel to an optical axis of the objective lens, and a shoulder portion of the distal end and an outer surface of the plano-concave lens located at the should portion are inclined so as to become narrower toward the tip.
