Optical element with attenuating region and method for manufacturing same

Provided is an optical element which optically couples a light-emitting element functioning as a light source and a light-receiving element, can be easily manufactured, and can achieve a desired transmittance over a wide range with high precision. The optical element has an incidence lens surface (111) configured to face a light source and an emission lens surface (131) configured to face a light receiving element so as to optically couple the light source and the light receiving element receiving light from the light source, and has an attenuation region for light incident from the incidence lens surface (111) and reaching the emission lens surface (131). Wherein the optical element is further provided with an additional lens surface (LLP) except for the incident lens surface (111) and the emergent lens surface (131), and a positioning surface for other light sources, which is used by the additional lens surface (LLP); the additional lens surface (LLP) is configured such that a conjugate point of an intersec