This optical receptacle has: a first optical surface on which light emitted from a photoelectric conversion element is incident; a second optical surface for emitting the light incident on the first optical surface to an end surface of an optical transmission body; a light separating part for separating the light incident on the first optical surface into signal light oriented toward the end surface of the optical transmission body and monitor light oriented toward a detection element so as to proceed in a direction substantially opposite to the progress direction of the signal light; and a third optical surface for emitting the monitor light separated by the light separating part toward the detection element. The entire optical path between the first optical surface and the second optical surface is positioned inside the optical receptacle.