An optical scanner includes a light source, an optical splitter which splits light from the light source into a plurality of light beams, an input optical element on which the light beams split by the optical splitter are incident, a driver which generates a voltage signal, an optical deflector which comprises at least two deflector portions formed close to each other on a same substrate and individually supplied with an electric action of the driver so as to capture and deflect the incident light beams using the electric action, and an output optical element which emits the deflected light beams to an image plane, wherein the optical scanner is configured to scan the image plane with the light beams by adjusting the voltage signal of the driver.