An endoscope includes: a first illumination optical system which emits illuminating light in a first linear polarization direction to an object from a distal end face of an insertion portion; and a first objective optical system which allows return light from the object to enter through an objective window provided in the distal end face; wherein the first illumination optical system and the first objective optical system are placed in a positional relationship such that on the distal end face, a line segment connecting an optical axis of the first illumination optical system and an optical axis of the first objective optical system is parallel or perpendicular to a polarization direction which results when the illuminating light emitted from the first illumination optical system is projected to the distal end face, and no polarizing element is provided between the object and the objective window.