There is provided an endoscope insertion portion capable of ensuring an excellent observation field of view by surely cleaning filth attached to an outer surface of a respective observation optical system. The endoscope insertion portion of this invention includes: an insertion portion including a distal end portion and provided inside with a duct having an inner circumferential length allowing a medical instrument to be inserted a first image pickup portion for obtaining a first observation image a second image pickup portion for obtaining a second observation image a first observation optical system for condensing light incident on the first image pickup portion, which is disposed at the distal end portion a second observation optical system for condensing light incident on the second image pickup portion, which is disposed at the distal end portion and an aperture portion disposed on a distal end surface of the distal end portion so as to be in communication with the duct. On the distal end surface, a distance between a center of the aperture portion and a center of the first observation optical system is shorter than a distance between the center of the aperture portion and a center of the second observation optical system.
