Optical device and direction display device

An optical device for displaying a condensing mark, comprising:

• a light source;
• and
• an optical element having a deflection surface for condensing a light emitted from the light source, wherein
• the deflection surface is divided into at least more than two regions,
• lights deflected through the regions on the deflection surface of the optical element, respectively, form partial irradiation images on an irradiated surface, and each partial irradiation image has a different shape at a different location on an irradiated surface for each region on the deflection surface,
• the partial irradiation images are combined with each other to form at least one condensing mark on the irradiated surface, and
• the regions on the deflection surface of the optical element which correspond, respectively, to the partial irradiation images forming the one condensing mark have different values of direction cosines at the boundary area than adjacent regions and different free-form surface shapes than adjacent regions.