An optical intermediary component is suitable for guiding a light from an output optical path into an input optical path. The optical intermediary component includes a light guiding portion extending along a light axis. The light guiding portion has a light incident surface and a light emitting surface at two opposite ends thereof respectively. The light from the output optical path passes through the light incident surface and the light emitting surface of the light guiding portion in sequence, and is guided into the input optical path. The area of the light incident surface is greater than that of the light emitting surface. Therefore, a high assembly tolerance may reduce the manufacturing and assembly cost.